/* vi:set ts=8 sts=4 sw=4 noet:
 *
 * VIM - Vi IMproved	by Bram Moolenaar
 *	      OS/2 port by Paul Slootman
 *	      VMS merge by Zoltan Arpadffy
 *
 * Do ":help uganda"  in Vim to read copying and usage conditions.
 * Do ":help credits" in Vim to see a list of people who contributed.
 * See README.txt for an overview of the Vim source code.
 */

/*
 * os_unix.c -- code for all flavors of Unix (BSD, SYSV, SVR4, POSIX, ...)
 *	     Also for OS/2, using the excellent EMX package!!!
 *	     Also for BeOS and Atari MiNT.
 *
 * A lot of this file was originally written by Juergen Weigert and later
 * changed beyond recognition.
 */

#include "vim.h"

#ifdef FEAT_MZSCHEME
# include "if_mzsch.h"
#endif

#include "os_unixx.h"	    /* unix includes for os_unix.c only */

#ifdef USE_XSMP
# include <X11/SM/SMlib.h>
#endif

#ifdef HAVE_SELINUX
# include <selinux/selinux.h>
static int selinux_enabled = -1;
#endif

#ifdef HAVE_SMACK
# include <attr/xattr.h>
# include <linux/xattr.h>
# ifndef SMACK_LABEL_LEN
#  define SMACK_LABEL_LEN 1024
# endif
#endif

#ifdef __BEOS__
# undef select
# define select	beos_select
#endif

#ifdef __CYGWIN__
# ifndef WIN32
#  include <cygwin/version.h>
#  include <sys/cygwin.h>	/* for cygwin_conv_to_posix_path() and/or
				 * for cygwin_conv_path() */
#  ifdef FEAT_CYGWIN_WIN32_CLIPBOARD
#   define WIN32_LEAN_AND_MEAN
#   include <windows.h>
#   include "winclip.pro"
#  endif
# endif
#endif

#ifdef FEAT_MOUSE_GPM
# include <gpm.h>
/* <linux/keyboard.h> contains defines conflicting with "keymap.h",
 * I just copied relevant defines here. A cleaner solution would be to put gpm
 * code into separate file and include there linux/keyboard.h
 */
/* #include <linux/keyboard.h> */
# define KG_SHIFT	0
# define KG_CTRL	2
# define KG_ALT		3
# define KG_ALTGR	1
# define KG_SHIFTL	4
# define KG_SHIFTR	5
# define KG_CTRLL	6
# define KG_CTRLR	7
# define KG_CAPSSHIFT	8

static void gpm_close(void);
static int gpm_open(void);
static int mch_gpm_process(void);
#endif

#ifdef FEAT_SYSMOUSE
# include <sys/consio.h>
# include <sys/fbio.h>

static int sysmouse_open(void);
static void sysmouse_close(void);
static RETSIGTYPE sig_sysmouse SIGPROTOARG;
#endif

/*
 * end of autoconf section. To be extended...
 */

/* Are the following #ifdefs still required? And why? Is that for X11? */

#if defined(ESIX) || defined(M_UNIX) && !defined(SCO)
# ifdef SIGWINCH
#  undef SIGWINCH
# endif
# ifdef TIOCGWINSZ
#  undef TIOCGWINSZ
# endif
#endif

#if defined(SIGWINDOW) && !defined(SIGWINCH)	/* hpux 9.01 has it */
# define SIGWINCH SIGWINDOW
#endif

#ifdef FEAT_X11
# include <X11/Xlib.h>
# include <X11/Xutil.h>
# include <X11/Xatom.h>
# ifdef FEAT_XCLIPBOARD
#  include <X11/Intrinsic.h>
#  include <X11/Shell.h>
#  include <X11/StringDefs.h>
static Widget	xterm_Shell = (Widget)0;
static void clip_update(void);
static void xterm_update(void);
# endif

# if defined(FEAT_XCLIPBOARD) || defined(FEAT_TITLE)
Window	    x11_window = 0;
# endif
Display	    *x11_display = NULL;
#endif

#ifdef FEAT_TITLE
static int get_x11_title(int);

static char_u	*oldtitle = NULL;
static volatile sig_atomic_t oldtitle_outdated = FALSE;
static int	did_set_title = FALSE;
static char_u	*oldicon = NULL;
static int	did_set_icon = FALSE;
#endif

static void may_core_dump(void);

#ifdef HAVE_UNION_WAIT
typedef union wait waitstatus;
#else
typedef int waitstatus;
#endif
static int  WaitForChar(long msec, int *interrupted, int ignore_input);
static int  WaitForCharOrMouse(long msec, int *interrupted, int ignore_input);
#if defined(__BEOS__) || defined(VMS)
int  RealWaitForChar(int, long, int *, int *interrupted);
#else
static int  RealWaitForChar(int, long, int *, int *interrupted);
#endif

#ifdef FEAT_XCLIPBOARD
static int do_xterm_trace(void);
# define XT_TRACE_DELAY	50	/* delay for xterm tracing */
#endif

static void handle_resize(void);

#if defined(SIGWINCH)
static RETSIGTYPE sig_winch SIGPROTOARG;
#endif
#if defined(SIGINT)
static RETSIGTYPE catch_sigint SIGPROTOARG;
#endif
#if defined(SIGPWR)
static RETSIGTYPE catch_sigpwr SIGPROTOARG;
#endif
#if defined(SIGALRM) && defined(FEAT_X11) \
	&& defined(FEAT_TITLE) && !defined(FEAT_GUI_GTK)
# define SET_SIG_ALARM
static RETSIGTYPE sig_alarm SIGPROTOARG;
/* volatile because it is used in signal handler sig_alarm(). */
static volatile sig_atomic_t sig_alarm_called;
#endif
static RETSIGTYPE deathtrap SIGPROTOARG;

static void catch_int_signal(void);
static void set_signals(void);
static void catch_signals(RETSIGTYPE (*func_deadly)(), RETSIGTYPE (*func_other)());
#ifdef HAVE_SIGPROCMASK
# define SIGSET_DECL(set)	sigset_t set;
# define BLOCK_SIGNALS(set)	block_signals(set)
# define UNBLOCK_SIGNALS(set)	unblock_signals(set)
#else
# define SIGSET_DECL(set)
# define BLOCK_SIGNALS(set)	do { /**/ } while (0)
# define UNBLOCK_SIGNALS(set)	do { /**/ } while (0)
#endif
static int  have_wildcard(int, char_u **);
static int  have_dollars(int, char_u **);

static int save_patterns(int num_pat, char_u **pat, int *num_file, char_u ***file);

#ifndef SIG_ERR
# define SIG_ERR	((RETSIGTYPE (*)())-1)
#endif

/* volatile because it is used in signal handler sig_winch(). */
static volatile sig_atomic_t do_resize = FALSE;
static char_u	*extra_shell_arg = NULL;
static int	show_shell_mess = TRUE;
/* volatile because it is used in signal handler deathtrap(). */
static volatile sig_atomic_t deadly_signal = 0;	   /* The signal we caught */
/* volatile because it is used in signal handler deathtrap(). */
static volatile sig_atomic_t in_mch_delay = FALSE; /* sleeping in mch_delay() */

#if defined(FEAT_JOB_CHANNEL) && !defined(USE_SYSTEM)
static int dont_check_job_ended = 0;
#endif

static int curr_tmode = TMODE_COOK;	/* contains current terminal mode */

#ifdef USE_XSMP
typedef struct
{
    SmcConn smcconn;	    /* The SM connection ID */
    IceConn iceconn;	    /* The ICE connection ID */
    char *clientid;	    /* The client ID for the current smc session */
    Bool save_yourself;     /* If we're in the middle of a save_yourself */
    Bool shutdown;	    /* If we're in shutdown mode */
} xsmp_config_T;

static xsmp_config_T xsmp;
#endif

#ifdef SYS_SIGLIST_DECLARED
/*
 * I have seen
 *  extern char *_sys_siglist[NSIG];
 * on Irix, Linux, NetBSD and Solaris. It contains a nice list of strings
 * that describe the signals. That is nearly what we want here.  But
 * autoconf does only check for sys_siglist (without the underscore), I
 * do not want to change everything today.... jw.
 * This is why AC_DECL_SYS_SIGLIST is commented out in configure.ac.
 */
#endif

static struct signalinfo
{
    int	    sig;	/* Signal number, eg. SIGSEGV etc */
    char    *name;	/* Signal name (not char_u!). */
    char    deadly;	/* Catch as a deadly signal? */
} signal_info[] =
{
#ifdef SIGHUP
    {SIGHUP,	    "HUP",	TRUE},
#endif
#ifdef SIGQUIT
    {SIGQUIT,	    "QUIT",	TRUE},
#endif
#ifdef SIGILL
    {SIGILL,	    "ILL",	TRUE},
#endif
#ifdef SIGTRAP
    {SIGTRAP,	    "TRAP",	TRUE},
#endif
#ifdef SIGABRT
    {SIGABRT,	    "ABRT",	TRUE},
#endif
#ifdef SIGEMT
    {SIGEMT,	    "EMT",	TRUE},
#endif
#ifdef SIGFPE
    {SIGFPE,	    "FPE",	TRUE},
#endif
#ifdef SIGBUS
    {SIGBUS,	    "BUS",	TRUE},
#endif
#if defined(SIGSEGV) && !defined(FEAT_MZSCHEME)
    /* MzScheme uses SEGV in its garbage collector */
    {SIGSEGV,	    "SEGV",	TRUE},
#endif
#ifdef SIGSYS
    {SIGSYS,	    "SYS",	TRUE},
#endif
#ifdef SIGALRM
    {SIGALRM,	    "ALRM",	FALSE},	/* Perl's alarm() can trigger it */
#endif
#ifdef SIGTERM
    {SIGTERM,	    "TERM",	TRUE},
#endif
#if defined(SIGVTALRM) && !defined(FEAT_RUBY)
    {SIGVTALRM,	    "VTALRM",	TRUE},
#endif
#if defined(SIGPROF) && !defined(FEAT_MZSCHEME) && !defined(WE_ARE_PROFILING)
    /* MzScheme uses SIGPROF for its own needs; On Linux with profiling
     * this makes Vim exit.  WE_ARE_PROFILING is defined in Makefile.  */
    {SIGPROF,	    "PROF",	TRUE},
#endif
#ifdef SIGXCPU
    {SIGXCPU,	    "XCPU",	TRUE},
#endif
#ifdef SIGXFSZ
    {SIGXFSZ,	    "XFSZ",	TRUE},
#endif
#ifdef SIGUSR1
    {SIGUSR1,	    "USR1",	TRUE},
#endif
#if defined(SIGUSR2) && !defined(FEAT_SYSMOUSE)
    /* Used for sysmouse handling */
    {SIGUSR2,	    "USR2",	TRUE},
#endif
#ifdef SIGINT
    {SIGINT,	    "INT",	FALSE},
#endif
#ifdef SIGWINCH
    {SIGWINCH,	    "WINCH",	FALSE},
#endif
#ifdef SIGTSTP
    {SIGTSTP,	    "TSTP",	FALSE},
#endif
#ifdef SIGPIPE
    {SIGPIPE,	    "PIPE",	FALSE},
#endif
    {-1,	    "Unknown!", FALSE}
};

    int
mch_chdir(char *path)
{
    if (p_verbose >= 5)
    {
	verbose_enter();
	smsg("chdir(%s)", path);
	verbose_leave();
    }
# ifdef VMS
    return chdir(vms_fixfilename(path));
# else
    return chdir(path);
# endif
}

/* Why is NeXT excluded here (and not in os_unixx.h)? */
#if defined(ECHOE) && defined(ICANON) && (defined(HAVE_TERMIO_H) || defined(HAVE_TERMIOS_H)) && !defined(__NeXT__)
# define NEW_TTY_SYSTEM
#endif

/*
 * Write s[len] to the screen (stdout).
 */
    void
mch_write(char_u *s, int len)
{
    vim_ignored = (int)write(1, (char *)s, len);
    if (p_wd)		/* Unix is too fast, slow down a bit more */
	RealWaitForChar(read_cmd_fd, p_wd, NULL, NULL);
}

/*
 * mch_inchar(): low level input function.
 * Get a characters from the keyboard.
 * Return the number of characters that are available.
 * If wtime == 0 do not wait for characters.
 * If wtime == n wait a short time for characters.
 * If wtime == -1 wait forever for characters.
 */
    int
mch_inchar(
    char_u	*buf,
    int		maxlen,
    long	wtime,	    /* don't use "time", MIPS cannot handle it */
    int		tb_change_cnt)
{
    int		len;
    int		interrupted = FALSE;
    int		did_start_blocking = FALSE;
    long	wait_time;
    long	elapsed_time = 0;
#ifdef ELAPSED_FUNC
    elapsed_T	start_tv;

    ELAPSED_INIT(start_tv);
#endif

    /* repeat until we got a character or waited long enough */
    for (;;)
    {
	/* Check if window changed size while we were busy, perhaps the ":set
	 * columns=99" command was used. */
	while (do_resize)
	    handle_resize();

#ifdef MESSAGE_QUEUE
	// Only process messages when waiting.
	if (wtime != 0)
	{
	    parse_queued_messages();
	    // If input was put directly in typeahead buffer bail out here.
	    if (typebuf_changed(tb_change_cnt))
		return 0;
	}
#endif
	if (wtime < 0 && did_start_blocking)
	    /* blocking and already waited for p_ut */
	    wait_time = -1;
	else
	{
	    if (wtime >= 0)
		wait_time = wtime;
	    else
		/* going to block after p_ut */
		wait_time = p_ut;
#ifdef ELAPSED_FUNC
	    elapsed_time = ELAPSED_FUNC(start_tv);
#endif
	    wait_time -= elapsed_time;
	    if (wait_time < 0)
	    {
		if (wtime >= 0)
		    /* no character available within "wtime" */
		    return 0;

		else
		{
		    /* no character available within 'updatetime' */
		    did_start_blocking = TRUE;
		    if (trigger_cursorhold() && maxlen >= 3
					    && !typebuf_changed(tb_change_cnt))
		    {
			buf[0] = K_SPECIAL;
			buf[1] = KS_EXTRA;
			buf[2] = (int)KE_CURSORHOLD;
			return 3;
		    }
		    /*
		     * If there is no character available within 'updatetime'
		     * seconds flush all the swap files to disk.
		     * Also done when interrupted by SIGWINCH.
		     */
		    before_blocking();
		    continue;
		}
	    }
	}

#ifdef FEAT_JOB_CHANNEL
	/* Checking if a job ended requires polling.  Do this every 100 msec. */
	if (has_pending_job() && (wait_time < 0 || wait_time > 100L))
	    wait_time = 100L;
	/* If there is readahead then parse_queued_messages() timed out and we
	 * should call it again soon. */
	if ((wait_time < 0 || wait_time > 100L) && channel_any_readahead())
	    wait_time = 10L;
#endif
#ifdef FEAT_BEVAL_GUI
	if (p_beval && wait_time > 100L)
	    /* The 'balloonexpr' may indirectly invoke a callback while waiting
	     * for a character, need to check often. */
	    wait_time = 100L;
#endif

	/*
	 * We want to be interrupted by the winch signal
	 * or by an event on the monitored file descriptors.
	 */
	if (WaitForChar(wait_time, &interrupted, FALSE))
	{
	    /* If input was put directly in typeahead buffer bail out here. */
	    if (typebuf_changed(tb_change_cnt))
		return 0;

	    /*
	     * For some terminals we only get one character at a time.
	     * We want the get all available characters, so we could keep on
	     * trying until none is available
	     * For some other terminals this is quite slow, that's why we don't
	     * do it.
	     */
	    len = read_from_input_buf(buf, (long)maxlen);
	    if (len > 0)
		return len;
	    continue;
	}

	/* no character available */
#ifndef ELAPSED_FUNC
	/* estimate the elapsed time */
	elapsed_time += wait_time;
#endif

	if (do_resize	    /* interrupted by SIGWINCH signal */
#ifdef FEAT_CLIENTSERVER
		|| server_waiting()
#endif
#ifdef MESSAGE_QUEUE
		|| interrupted
#endif
		|| wait_time > 0
		|| (wtime < 0 && !did_start_blocking))
	    continue;

	/* no character available or interrupted */
	break;
    }
    return 0;
}

    static void
handle_resize(void)
{
    do_resize = FALSE;
    shell_resized();
}

/*
 * Return non-zero if a character is available.
 */
    int
mch_char_avail(void)
{
    return WaitForChar(0L, NULL, FALSE);
}

#if defined(FEAT_TERMINAL) || defined(PROTO)
/*
 * Check for any pending input or messages.
 */
    int
mch_check_messages(void)
{
    return WaitForChar(0L, NULL, TRUE);
}
#endif

#if defined(HAVE_TOTAL_MEM) || defined(PROTO)
# ifdef HAVE_SYS_RESOURCE_H
#  include <sys/resource.h>
# endif
# if defined(HAVE_SYS_SYSCTL_H) && defined(HAVE_SYSCTL)
#  include <sys/sysctl.h>
# endif
# if defined(HAVE_SYS_SYSINFO_H) && defined(HAVE_SYSINFO)
#  include <sys/sysinfo.h>
# endif
# ifdef MACOS_X
#  include <mach/mach_host.h>
#  include <mach/mach_port.h>
# endif

/*
 * Return total amount of memory available in Kbyte.
 * Doesn't change when memory has been allocated.
 */
    long_u
mch_total_mem(int special UNUSED)
{
    long_u	mem = 0;
    long_u	shiftright = 10;  /* how much to shift "mem" right for Kbyte */

# ifdef MACOS_X
    {
	/* Mac (Darwin) way of getting the amount of RAM available */
	mach_port_t		host = mach_host_self();
	kern_return_t		kret;
#  ifdef HOST_VM_INFO64
	struct vm_statistics64	vm_stat;
	natural_t		count = HOST_VM_INFO64_COUNT;

	kret = host_statistics64(host, HOST_VM_INFO64,
					     (host_info64_t)&vm_stat, &count);
#  else
	struct vm_statistics	vm_stat;
	natural_t		count = HOST_VM_INFO_COUNT;

	kret = host_statistics(host, HOST_VM_INFO,
					       (host_info_t)&vm_stat, &count);
#  endif
	if (kret == KERN_SUCCESS)
	    /* get the amount of user memory by summing each usage */
	    mem = (long_u)(vm_stat.free_count + vm_stat.active_count
					    + vm_stat.inactive_count
#  ifdef MAC_OS_X_VERSION_10_9
					    + vm_stat.compressor_page_count
#  endif
					    ) * sysconf(_SC_PAGESIZE);
	mach_port_deallocate(mach_task_self(), host);
    }
# endif

# ifdef HAVE_SYSCTL
    if (mem == 0)
    {
	/* BSD way of getting the amount of RAM available. */
	int		mib[2];
	size_t		len = sizeof(long_u);
#  ifdef HW_USERMEM64
	long_u		physmem;
#  else
	/* sysctl() may return 32 bit or 64 bit, accept both */
	union {
	    int_u	u32;
	    long_u	u64;
	} physmem;
#  endif

	mib[0] = CTL_HW;
#  ifdef HW_USERMEM64
	mib[1] = HW_USERMEM64;
#  else
	mib[1] = HW_USERMEM;
#  endif
	if (sysctl(mib, 2, &physmem, &len, NULL, 0) == 0)
	{
#  ifdef HW_USERMEM64
	    mem = (long_u)physmem;
#  else
	    if (len == sizeof(physmem.u64))
		mem = (long_u)physmem.u64;
	    else
		mem = (long_u)physmem.u32;
#  endif
	}
    }
# endif

# if defined(HAVE_SYS_SYSINFO_H) && defined(HAVE_SYSINFO)
    if (mem == 0)
    {
	struct sysinfo sinfo;

	/* Linux way of getting amount of RAM available */
	if (sysinfo(&sinfo) == 0)
	{
#  ifdef HAVE_SYSINFO_MEM_UNIT
	    /* avoid overflow as much as possible */
	    while (shiftright > 0 && (sinfo.mem_unit & 1) == 0)
	    {
		sinfo.mem_unit = sinfo.mem_unit >> 1;
		--shiftright;
	    }
	    mem = sinfo.totalram * sinfo.mem_unit;
#  else
	    mem = sinfo.totalram;
#  endif
	}
    }
# endif

# ifdef HAVE_SYSCONF
    if (mem == 0)
    {
	long	    pagesize, pagecount;

	/* Solaris way of getting amount of RAM available */
	pagesize = sysconf(_SC_PAGESIZE);
	pagecount = sysconf(_SC_PHYS_PAGES);
	if (pagesize > 0 && pagecount > 0)
	{
	    /* avoid overflow as much as possible */
	    while (shiftright > 0 && (pagesize & 1) == 0)
	    {
		pagesize = (long_u)pagesize >> 1;
		--shiftright;
	    }
	    mem = (long_u)pagesize * pagecount;
	}
    }
# endif

    /* Return the minimum of the physical memory and the user limit, because
     * using more than the user limit may cause Vim to be terminated. */
# if defined(HAVE_SYS_RESOURCE_H) && defined(HAVE_GETRLIMIT)
    {
	struct rlimit	rlp;

	if (getrlimit(RLIMIT_DATA, &rlp) == 0
		&& rlp.rlim_cur < ((rlim_t)1 << (sizeof(long_u) * 8 - 1))
#  ifdef RLIM_INFINITY
		&& rlp.rlim_cur != RLIM_INFINITY
#  endif
		&& ((long_u)rlp.rlim_cur >> 10) < (mem >> shiftright)
	   )
	{
	    mem = (long_u)rlp.rlim_cur;
	    shiftright = 10;
	}
    }
# endif

    if (mem > 0)
	return mem >> shiftright;
    return (long_u)0x1fffff;
}
#endif

    void
mch_delay(long msec, int ignoreinput)
{
    int		old_tmode;
#ifdef FEAT_MZSCHEME
    long	total = msec; /* remember original value */
#endif

    if (ignoreinput)
    {
	/* Go to cooked mode without echo, to allow SIGINT interrupting us
	 * here.  But we don't want QUIT to kill us (CTRL-\ used in a
	 * shell may produce SIGQUIT). */
	in_mch_delay = TRUE;
	old_tmode = curr_tmode;
	if (curr_tmode == TMODE_RAW)
	    settmode(TMODE_SLEEP);

	/*
	 * Everybody sleeps in a different way...
	 * Prefer nanosleep(), some versions of usleep() can only sleep up to
	 * one second.
	 */
#ifdef FEAT_MZSCHEME
	do
	{
	    /* if total is large enough, wait by portions in p_mzq */
	    if (total > p_mzq)
		msec = p_mzq;
	    else
		msec = total;
	    total -= msec;
#endif
#ifdef HAVE_NANOSLEEP
	{
	    struct timespec ts;

	    ts.tv_sec = msec / 1000;
	    ts.tv_nsec = (msec % 1000) * 1000000;
	    (void)nanosleep(&ts, NULL);
	}
#else
# ifdef HAVE_USLEEP
	while (msec >= 1000)
	{
	    usleep((unsigned int)(999 * 1000));
	    msec -= 999;
	}
	usleep((unsigned int)(msec * 1000));
# else
#  ifndef HAVE_SELECT
	poll(NULL, 0, (int)msec);
#  else
	{
	    struct timeval tv;

	    tv.tv_sec = msec / 1000;
	    tv.tv_usec = (msec % 1000) * 1000;
	    /*
	     * NOTE: Solaris 2.6 has a bug that makes select() hang here.  Get
	     * a patch from Sun to fix this.  Reported by Gunnar Pedersen.
	     */
	    select(0, NULL, NULL, NULL, &tv);
	}
#  endif /* HAVE_SELECT */
# endif /* HAVE_NANOSLEEP */
#endif /* HAVE_USLEEP */
#ifdef FEAT_MZSCHEME
	}
	while (total > 0);
#endif

	settmode(old_tmode);
	in_mch_delay = FALSE;
    }
    else
	WaitForChar(msec, NULL, FALSE);
}

#if defined(HAVE_STACK_LIMIT) \
	|| (!defined(HAVE_SIGALTSTACK) && defined(HAVE_SIGSTACK))
# define HAVE_CHECK_STACK_GROWTH
/*
 * Support for checking for an almost-out-of-stack-space situation.
 */

/*
 * Return a pointer to an item on the stack.  Used to find out if the stack
 * grows up or down.
 */
static int stack_grows_downwards;

/*
 * Find out if the stack grows upwards or downwards.
 * "p" points to a variable on the stack of the caller.
 */
    static void
check_stack_growth(char *p)
{
    int		i;

    stack_grows_downwards = (p > (char *)&i);
}
#endif

#if defined(HAVE_STACK_LIMIT) || defined(PROTO)
static char *stack_limit = NULL;

#if defined(_THREAD_SAFE) && defined(HAVE_PTHREAD_NP_H)
# include <pthread.h>
# include <pthread_np.h>
#endif

/*
 * Find out until how var the stack can grow without getting into trouble.
 * Called when starting up and when switching to the signal stack in
 * deathtrap().
 */
    static void
get_stack_limit(void)
{
    struct rlimit	rlp;
    int			i;
    long		lim;

    /* Set the stack limit to 15/16 of the allowable size.  Skip this when the
     * limit doesn't fit in a long (rlim_cur might be "long long"). */
    if (getrlimit(RLIMIT_STACK, &rlp) == 0
	    && rlp.rlim_cur < ((rlim_t)1 << (sizeof(long_u) * 8 - 1))
#  ifdef RLIM_INFINITY
	    && rlp.rlim_cur != RLIM_INFINITY
#  endif
       )
    {
	lim = (long)rlp.rlim_cur;
#if defined(_THREAD_SAFE) && defined(HAVE_PTHREAD_NP_H)
	{
	    pthread_attr_t  attr;
	    size_t	    size;

	    /* On FreeBSD the initial thread always has a fixed stack size, no
	     * matter what the limits are set to.  Normally it's 1 Mbyte. */
	    pthread_attr_init(&attr);
	    if (pthread_attr_get_np(pthread_self(), &attr) == 0)
	    {
		pthread_attr_getstacksize(&attr, &size);
		if (lim > (long)size)
		    lim = (long)size;
	    }
	    pthread_attr_destroy(&attr);
	}
#endif
	if (stack_grows_downwards)
	{
	    stack_limit = (char *)((long)&i - (lim / 16L * 15L));
	    if (stack_limit >= (char *)&i)
		/* overflow, set to 1/16 of current stack position */
		stack_limit = (char *)((long)&i / 16L);
	}
	else
	{
	    stack_limit = (char *)((long)&i + (lim / 16L * 15L));
	    if (stack_limit <= (char *)&i)
		stack_limit = NULL;	/* overflow */
	}
    }
}

/*
 * Return FAIL when running out of stack space.
 * "p" must point to any variable local to the caller that's on the stack.
 */
    int
mch_stackcheck(char *p)
{
    if (stack_limit != NULL)
    {
	if (stack_grows_downwards)
	{
	    if (p < stack_limit)
		return FAIL;
	}
	else if (p > stack_limit)
	    return FAIL;
    }
    return OK;
}
#endif

#if defined(HAVE_SIGALTSTACK) || defined(HAVE_SIGSTACK)
/*
 * Support for using the signal stack.
 * This helps when we run out of stack space, which causes a SIGSEGV.  The
 * signal handler then must run on another stack, since the normal stack is
 * completely full.
 */

#ifndef SIGSTKSZ
# define SIGSTKSZ 8000    /* just a guess of how much stack is needed... */
#endif

# ifdef HAVE_SIGALTSTACK
static stack_t sigstk;			/* for sigaltstack() */
# else
static struct sigstack sigstk;		/* for sigstack() */
# endif

static char *signal_stack;

    static void
init_signal_stack(void)
{
    if (signal_stack != NULL)
    {
# ifdef HAVE_SIGALTSTACK
#  ifdef HAVE_SS_BASE
	sigstk.ss_base = signal_stack;
#  else
	sigstk.ss_sp = signal_stack;
#  endif
	sigstk.ss_size = SIGSTKSZ;
	sigstk.ss_flags = 0;
	(void)sigaltstack(&sigstk, NULL);
# else
	sigstk.ss_sp = signal_stack;
	if (stack_grows_downwards)
	    sigstk.ss_sp += SIGSTKSZ - 1;
	sigstk.ss_onstack = 0;
	(void)sigstack(&sigstk, NULL);
# endif
    }
}
#endif

/*
 * We need correct prototypes for a signal function, otherwise mean compilers
 * will barf when the second argument to signal() is ``wrong''.
 * Let me try it with a few tricky defines from my own osdef.h	(jw).
 */
#if defined(SIGWINCH)
    static RETSIGTYPE
sig_winch SIGDEFARG(sigarg)
{
    /* this is not required on all systems, but it doesn't hurt anybody */
    signal(SIGWINCH, (RETSIGTYPE (*)())sig_winch);
    do_resize = TRUE;
    SIGRETURN;
}
#endif

#if defined(SIGINT)
    static RETSIGTYPE
catch_sigint SIGDEFARG(sigarg)
{
    /* this is not required on all systems, but it doesn't hurt anybody */
    signal(SIGINT, (RETSIGTYPE (*)())catch_sigint);
    got_int = TRUE;
    SIGRETURN;
}
#endif

#if defined(SIGPWR)
    static RETSIGTYPE
catch_sigpwr SIGDEFARG(sigarg)
{
    /* this is not required on all systems, but it doesn't hurt anybody */
    signal(SIGPWR, (RETSIGTYPE (*)())catch_sigpwr);
    /*
     * I'm not sure we get the SIGPWR signal when the system is really going
     * down or when the batteries are almost empty.  Just preserve the swap
     * files and don't exit, that can't do any harm.
     */
    ml_sync_all(FALSE, FALSE);
    SIGRETURN;
}
#endif

#ifdef SET_SIG_ALARM
/*
 * signal function for alarm().
 */
    static RETSIGTYPE
sig_alarm SIGDEFARG(sigarg)
{
    /* doesn't do anything, just to break a system call */
    sig_alarm_called = TRUE;
    SIGRETURN;
}
#endif

#if defined(HAVE_SETJMP_H) || defined(PROTO)
// argument to SETJMP()
static JMP_BUF lc_jump_env;

# ifdef SIGHASARG
// Caught signal number, 0 when no was signal caught; used for mch_libcall().
// Volatile because it is used in signal handlers.
static volatile sig_atomic_t lc_signal;
# endif

// TRUE when lc_jump_env is valid.
// Volatile because it is used in signal handler deathtrap().
static volatile sig_atomic_t lc_active INIT(= FALSE);

/*
 * A simplistic version of setjmp() that only allows one level of using.
 * Used to protect areas where we could crash.
 * Don't call twice before calling mch_endjmp()!.
 *
 * Usage:
 *	mch_startjmp();
 *	if (SETJMP(lc_jump_env) != 0)
 *	{
 *	    mch_didjmp();
 *	    emsg("crash!");
 *	}
 *	else
 *	{
 *	    do_the_work;
 *	    mch_endjmp();
 *	}
 * Note: Can't move SETJMP() here, because a function calling setjmp() must
 * not return before the saved environment is used.
 * Returns OK for normal return, FAIL when the protected code caused a
 * problem and LONGJMP() was used.
 */
    void
mch_startjmp(void)
{
#ifdef SIGHASARG
    lc_signal = 0;
#endif
    lc_active = TRUE;
}

    void
mch_endjmp(void)
{
    lc_active = FALSE;
}

    void
mch_didjmp(void)
{
# if defined(HAVE_SIGALTSTACK) || defined(HAVE_SIGSTACK)
    // On FreeBSD the signal stack has to be reset after using siglongjmp(),
    // otherwise catching the signal only works once.
    init_signal_stack();
# endif
}
#endif

/*
 * This function handles deadly signals.
 * It tries to preserve any swap files and exit properly.
 * (partly from Elvis).
 * NOTE: Avoid unsafe functions, such as allocating memory, they can result in
 * a deadlock.
 */
    static RETSIGTYPE
deathtrap SIGDEFARG(sigarg)
{
    static int	entered = 0;	    /* count the number of times we got here.
				       Note: when memory has been corrupted
				       this may get an arbitrary value! */
#ifdef SIGHASARG
    int		i;
#endif

#if defined(HAVE_SETJMP_H)
    /*
     * Catch a crash in protected code.
     * Restores the environment saved in lc_jump_env, which looks like
     * SETJMP() returns 1.
     */
    if (lc_active)
    {
# if defined(SIGHASARG)
	lc_signal = sigarg;
# endif
	lc_active = FALSE;	/* don't jump again */
	LONGJMP(lc_jump_env, 1);
	/* NOTREACHED */
    }
#endif

#ifdef SIGHASARG
# ifdef SIGQUIT
    /* While in mch_delay() we go to cooked mode to allow a CTRL-C to
     * interrupt us.  But in cooked mode we may also get SIGQUIT, e.g., when
     * pressing CTRL-\, but we don't want Vim to exit then. */
    if (in_mch_delay && sigarg == SIGQUIT)
	SIGRETURN;
# endif

    /* When SIGHUP, SIGQUIT, etc. are blocked: postpone the effect and return
     * here.  This avoids that a non-reentrant function is interrupted, e.g.,
     * free().  Calling free() again may then cause a crash. */
    if (entered == 0
	    && (0
# ifdef SIGHUP
		|| sigarg == SIGHUP
# endif
# ifdef SIGQUIT
		|| sigarg == SIGQUIT
# endif
# ifdef SIGTERM
		|| sigarg == SIGTERM
# endif
# ifdef SIGPWR
		|| sigarg == SIGPWR
# endif
# ifdef SIGUSR1
		|| sigarg == SIGUSR1
# endif
# ifdef SIGUSR2
		|| sigarg == SIGUSR2
# endif
		)
	    && !vim_handle_signal(sigarg))
	SIGRETURN;
#endif

    /* Remember how often we have been called. */
    ++entered;

    /* Executing autocommands is likely to use more stack space than we have
     * available in the signal stack. */
    block_autocmds();

#ifdef FEAT_EVAL
    /* Set the v:dying variable. */
    set_vim_var_nr(VV_DYING, (long)entered);
#endif
    v_dying = entered;

#ifdef HAVE_STACK_LIMIT
    /* Since we are now using the signal stack, need to reset the stack
     * limit.  Otherwise using a regexp will fail. */
    get_stack_limit();
#endif

#if 0
    /* This is for opening gdb the moment Vim crashes.
     * You need to manually adjust the file name and Vim executable name.
     * Suggested by SungHyun Nam. */
    {
# define VI_GDB_FILE "/tmp/vimgdb"
# define VIM_NAME "/usr/bin/vim"
	FILE *fp = fopen(VI_GDB_FILE, "w");
	if (fp)
	{
	    fprintf(fp,
		    "file %s\n"
		    "attach %d\n"
		    "set height 1000\n"
		    "bt full\n"
		    , VIM_NAME, getpid());
	    fclose(fp);
	    system("xterm -e gdb -x "VI_GDB_FILE);
	    unlink(VI_GDB_FILE);
	}
    }
#endif

#ifdef SIGHASARG
    /* try to find the name of this signal */
    for (i = 0; signal_info[i].sig != -1; i++)
	if (sigarg == signal_info[i].sig)
	    break;
    deadly_signal = sigarg;
#endif

    full_screen = FALSE;	/* don't write message to the GUI, it might be
				 * part of the problem... */
    /*
     * If something goes wrong after entering here, we may get here again.
     * When this happens, give a message and try to exit nicely (resetting the
     * terminal mode, etc.)
     * When this happens twice, just exit, don't even try to give a message,
     * stack may be corrupt or something weird.
     * When this still happens again (or memory was corrupted in such a way
     * that "entered" was clobbered) use _exit(), don't try freeing resources.
     */
    if (entered >= 3)
    {
	reset_signals();	/* don't catch any signals anymore */
	may_core_dump();
	if (entered >= 4)
	    _exit(8);
	exit(7);
    }
    if (entered == 2)
    {
	/* No translation, it may call malloc(). */
	OUT_STR("Vim: Double signal, exiting\n");
	out_flush();
	getout(1);
    }

    /* No translation, it may call malloc(). */
#ifdef SIGHASARG
    sprintf((char *)IObuff, "Vim: Caught deadly signal %s\n",
							 signal_info[i].name);
#else
    sprintf((char *)IObuff, "Vim: Caught deadly signal\n");
#endif

    /* Preserve files and exit.  This sets the really_exiting flag to prevent
     * calling free(). */
    preserve_exit();

    /* NOTREACHED */

#ifdef NBDEBUG
    reset_signals();
    may_core_dump();
    abort();
#endif

    SIGRETURN;
}

/*
 * Invoked after receiving SIGCONT.  We don't know what happened while
 * sleeping, deal with part of that.
 */
    static void
after_sigcont(void)
{
# ifdef FEAT_TITLE
    // Don't change "oldtitle" in a signal handler, set a flag to obtain it
    // again later.
    oldtitle_outdated = TRUE;
# endif
    settmode(TMODE_RAW);
    need_check_timestamps = TRUE;
    did_check_timestamps = FALSE;
}

#if defined(SIGCONT)
static RETSIGTYPE sigcont_handler SIGPROTOARG;
static volatile sig_atomic_t in_mch_suspend = FALSE;

/*
 * With multi-threading, suspending might not work immediately.  Catch the
 * SIGCONT signal, which will be used as an indication whether the suspending
 * has been done or not.
 *
 * On Linux, signal is not always handled immediately either.
 * See https://bugs.launchpad.net/bugs/291373
 * Probably because the signal is handled in another thread.
 *
 * volatile because it is used in signal handler sigcont_handler().
 */
static volatile sig_atomic_t sigcont_received;
static RETSIGTYPE sigcont_handler SIGPROTOARG;

/*
 * signal handler for SIGCONT
 */
    static RETSIGTYPE
sigcont_handler SIGDEFARG(sigarg)
{
    if (in_mch_suspend)
    {
	sigcont_received = TRUE;
    }
    else
    {
	// We didn't suspend ourselves, assume we were stopped by a SIGSTOP
	// signal (which can't be intercepted) and get a SIGCONT.  Need to get
	// back to a sane mode. We should redraw, but we can't really do that
	// in a signal handler, do a redraw later.
	after_sigcont();
	redraw_later(CLEAR);
	cursor_on_force();
	out_flush();
    }

    SIGRETURN;
}
#endif

#if defined(FEAT_CLIPBOARD) && defined(FEAT_X11)
# ifdef USE_SYSTEM
static void *clip_star_save = NULL;
static void *clip_plus_save = NULL;
# endif

/*
 * Called when Vim is going to sleep or execute a shell command.
 * We can't respond to requests for the X selections.  Lose them, otherwise
 * other applications will hang.  But first copy the text to cut buffer 0.
 */
    static void
loose_clipboard(void)
{
    if (clip_star.owned || clip_plus.owned)
    {
	x11_export_final_selection();
	if (clip_star.owned)
	    clip_lose_selection(&clip_star);
	if (clip_plus.owned)
	    clip_lose_selection(&clip_plus);
	if (x11_display != NULL)
	    XFlush(x11_display);
    }
}

# ifdef USE_SYSTEM
/*
 * Save clipboard text to restore later.
 */
    static void
save_clipboard(void)
{
    if (clip_star.owned)
	clip_star_save = get_register('*', TRUE);
    if (clip_plus.owned)
	clip_plus_save = get_register('+', TRUE);
}

/*
 * Restore clipboard text if no one own the X selection.
 */
    static void
restore_clipboard(void)
{
    if (clip_star_save != NULL)
    {
	if (!clip_gen_owner_exists(&clip_star))
	    put_register('*', clip_star_save);
	else
	    free_register(clip_star_save);
	clip_star_save = NULL;
    }
    if (clip_plus_save != NULL)
    {
	if (!clip_gen_owner_exists(&clip_plus))
	    put_register('+', clip_plus_save);
	else
	    free_register(clip_plus_save);
	clip_plus_save = NULL;
    }
}
# endif
#endif

/*
 * If the machine has job control, use it to suspend the program,
 * otherwise fake it by starting a new shell.
 */
    void
mch_suspend(void)
{
    /* BeOS does have SIGTSTP, but it doesn't work. */
#if defined(SIGTSTP) && !defined(__BEOS__)
    in_mch_suspend = TRUE;

    out_flush();	    /* needed to make cursor visible on some systems */
    settmode(TMODE_COOK);
    out_flush();	    /* needed to disable mouse on some systems */

# if defined(FEAT_CLIPBOARD) && defined(FEAT_X11)
    loose_clipboard();
# endif
# if defined(SIGCONT)
    sigcont_received = FALSE;
# endif

    kill(0, SIGTSTP);	    /* send ourselves a STOP signal */

# if defined(SIGCONT)
    /*
     * Wait for the SIGCONT signal to be handled. It generally happens
     * immediately, but somehow not all the time, probably because it's handled
     * in another thread. Do not call pause() because there would be race
     * condition which would hang Vim if signal happened in between the test of
     * sigcont_received and the call to pause(). If signal is not yet received,
     * sleep 0, 1, 2, 3 ms. Don't bother waiting further if signal is not
     * received after 1+2+3 ms (not expected to happen).
     */
    {
	long wait_time;

	for (wait_time = 0; !sigcont_received && wait_time <= 3L; wait_time++)
	    mch_delay(wait_time, FALSE);
    }
# endif
    in_mch_suspend = FALSE;

    after_sigcont();
#else
    suspend_shell();
#endif
}

    void
mch_init(void)
{
    Columns = 80;
    Rows = 24;

    out_flush();
    set_signals();

#ifdef MACOS_CONVERT
    mac_conv_init();
#endif
#ifdef FEAT_CYGWIN_WIN32_CLIPBOARD
    win_clip_init();
#endif
}

    static void
set_signals(void)
{
#if defined(SIGWINCH)
    /*
     * WINDOW CHANGE signal is handled with sig_winch().
     */
    signal(SIGWINCH, (RETSIGTYPE (*)())sig_winch);
#endif

    /*
     * We want the STOP signal to work, to make mch_suspend() work.
     * For "rvim" the STOP signal is ignored.
     */
#ifdef SIGTSTP
    signal(SIGTSTP, restricted ? SIG_IGN : SIG_DFL);
#endif
#if defined(SIGCONT)
    signal(SIGCONT, sigcont_handler);
#endif

    /*
     * We want to ignore breaking of PIPEs.
     */
#ifdef SIGPIPE
    signal(SIGPIPE, SIG_IGN);
#endif

#ifdef SIGINT
    catch_int_signal();
#endif

    /*
     * Ignore alarm signals (Perl's alarm() generates it).
     */
#ifdef SIGALRM
    signal(SIGALRM, SIG_IGN);
#endif

    /*
     * Catch SIGPWR (power failure?) to preserve the swap files, so that no
     * work will be lost.
     */
#ifdef SIGPWR
    signal(SIGPWR, (RETSIGTYPE (*)())catch_sigpwr);
#endif

    /*
     * Arrange for other signals to gracefully shutdown Vim.
     */
    catch_signals(deathtrap, SIG_ERR);

#if defined(FEAT_GUI) && defined(SIGHUP)
    /*
     * When the GUI is running, ignore the hangup signal.
     */
    if (gui.in_use)
	signal(SIGHUP, SIG_IGN);
#endif
}

#if defined(SIGINT) || defined(PROTO)
/*
 * Catch CTRL-C (only works while in Cooked mode).
 */
    static void
catch_int_signal(void)
{
    signal(SIGINT, (RETSIGTYPE (*)())catch_sigint);
}
#endif

    void
reset_signals(void)
{
    catch_signals(SIG_DFL, SIG_DFL);
#if defined(SIGCONT)
    /* SIGCONT isn't in the list, because its default action is ignore */
    signal(SIGCONT, SIG_DFL);
#endif
}

    static void
catch_signals(
    RETSIGTYPE (*func_deadly)(),
    RETSIGTYPE (*func_other)())
{
    int	    i;

    for (i = 0; signal_info[i].sig != -1; i++)
	if (signal_info[i].deadly)
	{
#if defined(HAVE_SIGALTSTACK) && defined(HAVE_SIGACTION)
	    struct sigaction sa;

	    /* Setup to use the alternate stack for the signal function. */
	    sa.sa_handler = func_deadly;
	    sigemptyset(&sa.sa_mask);
# if defined(__linux__) && defined(_REENTRANT)
	    /* On Linux, with glibc compiled for kernel 2.2, there is a bug in
	     * thread handling in combination with using the alternate stack:
	     * pthread library functions try to use the stack pointer to
	     * identify the current thread, causing a SEGV signal, which
	     * recursively calls deathtrap() and hangs. */
	    sa.sa_flags = 0;
# else
	    sa.sa_flags = SA_ONSTACK;
# endif
	    sigaction(signal_info[i].sig, &sa, NULL);
#else
# if defined(HAVE_SIGALTSTACK) && defined(HAVE_SIGVEC)
	    struct sigvec sv;

	    /* Setup to use the alternate stack for the signal function. */
	    sv.sv_handler = func_deadly;
	    sv.sv_mask = 0;
	    sv.sv_flags = SV_ONSTACK;
	    sigvec(signal_info[i].sig, &sv, NULL);
# else
	    signal(signal_info[i].sig, func_deadly);
# endif
#endif
	}
	else if (func_other != SIG_ERR)
	    signal(signal_info[i].sig, func_other);
}

#ifdef HAVE_SIGPROCMASK
    static void
block_signals(sigset_t *set)
{
    sigset_t	newset;
    int		i;

    sigemptyset(&newset);

    for (i = 0; signal_info[i].sig != -1; i++)
	sigaddset(&newset, signal_info[i].sig);

# if defined(SIGCONT)
    /* SIGCONT isn't in the list, because its default action is ignore */
    sigaddset(&newset, SIGCONT);
# endif

    sigprocmask(SIG_BLOCK, &newset, set);
}

    static void
unblock_signals(sigset_t *set)
{
    sigprocmask(SIG_SETMASK, set, NULL);
}
#endif

/*
 * Handling of SIGHUP, SIGQUIT and SIGTERM:
 * "when" == a signal:       when busy, postpone and return FALSE, otherwise
 *			     return TRUE
 * "when" == SIGNAL_BLOCK:   Going to be busy, block signals
 * "when" == SIGNAL_UNBLOCK: Going to wait, unblock signals, use postponed
 *			     signal
 * Returns TRUE when Vim should exit.
 */
    int
vim_handle_signal(int sig)
{
    static int got_signal = 0;
    static int blocked = TRUE;

    switch (sig)
    {
	case SIGNAL_BLOCK:   blocked = TRUE;
			     break;

	case SIGNAL_UNBLOCK: blocked = FALSE;
			     if (got_signal != 0)
			     {
				 kill(getpid(), got_signal);
				 got_signal = 0;
			     }
			     break;

	default:	     if (!blocked)
				 return TRUE;	/* exit! */
			     got_signal = sig;
#ifdef SIGPWR
			     if (sig != SIGPWR)
#endif
				 got_int = TRUE;    /* break any loops */
			     break;
    }
    return FALSE;
}

/*
 * Check_win checks whether we have an interactive stdout.
 */
    int
mch_check_win(int argc UNUSED, char **argv UNUSED)
{
    if (isatty(1))
	return OK;
    return FAIL;
}

/*
 * Return TRUE if the input comes from a terminal, FALSE otherwise.
 */
    int
mch_input_isatty(void)
{
    if (isatty(read_cmd_fd))
	return TRUE;
    return FALSE;
}

#ifdef FEAT_X11

# if defined(ELAPSED_TIMEVAL) \
	&& (defined(FEAT_XCLIPBOARD) || defined(FEAT_TITLE))

/*
 * Give a message about the elapsed time for opening the X window.
 */
    static void
xopen_message(long elapsed_msec)
{
    smsg(_("Opening the X display took %ld msec"), elapsed_msec);
}
# endif
#endif

#if defined(FEAT_X11) && (defined(FEAT_TITLE) || defined(FEAT_XCLIPBOARD))
/*
 * A few functions shared by X11 title and clipboard code.
 */

static int	got_x_error = FALSE;

/*
 * X Error handler, otherwise X just exits!  (very rude) -- webb
 */
    static int
x_error_handler(Display *dpy, XErrorEvent *error_event)
{
    XGetErrorText(dpy, error_event->error_code, (char *)IObuff, IOSIZE);
    STRCAT(IObuff, _("\nVim: Got X error\n"));

    /* We cannot print a message and continue, because no X calls are allowed
     * here (causes my system to hang).  Silently continuing might be an
     * alternative... */
    preserve_exit();		    /* preserve files and exit */

    return 0;		/* NOTREACHED */
}

/*
 * Another X Error handler, just used to check for errors.
 */
    static int
x_error_check(Display *dpy UNUSED, XErrorEvent *error_event UNUSED)
{
    got_x_error = TRUE;
    return 0;
}

/*
 * Return TRUE when connection to the X server is desired.
 */
    static int
x_connect_to_server(void)
{
    // No point in connecting if we are exiting or dying.
    if (exiting || v_dying)
	return FALSE;

#if defined(FEAT_CLIENTSERVER)
    if (x_force_connect)
	return TRUE;
#endif
    if (x_no_connect)
	return FALSE;

    // Check for a match with "exclude:" from 'clipboard'.
    if (clip_exclude_prog != NULL)
    {
	// Just in case we get called recursively, return FALSE.  This could
	// happen if vpeekc() is used while executing the prog and it causes a
	// related callback to be invoked.
	if (regprog_in_use(clip_exclude_prog))
	    return FALSE;

	if (vim_regexec_prog(&clip_exclude_prog, FALSE, T_NAME, (colnr_T)0))
	    return FALSE;
    }
    return TRUE;
}

#if defined(FEAT_X11) && defined(FEAT_XCLIPBOARD)
# if defined(HAVE_SETJMP_H)
/*
 * An X IO Error handler, used to catch error while opening the display.
 */
    static int
x_IOerror_check(Display *dpy UNUSED)
{
    /* This function should not return, it causes exit().  Longjump instead. */
    LONGJMP(lc_jump_env, 1);
#  if defined(VMS) || defined(__CYGWIN__) || defined(__CYGWIN32__)
    return 0;  /* avoid the compiler complains about missing return value */
#  endif
}
# endif

/*
 * An X IO Error handler, used to catch terminal errors.
 */
static int xterm_dpy_retry_count = 0;

    static int
x_IOerror_handler(Display *dpy UNUSED)
{
    xterm_dpy = NULL;
    xterm_dpy_retry_count = 5;  // Try reconnecting five times
    x11_window = 0;
    x11_display = NULL;
    xterm_Shell = (Widget)0;

    /* This function should not return, it causes exit().  Longjump instead. */
    LONGJMP(x_jump_env, 1);
# if defined(VMS) || defined(__CYGWIN__) || defined(__CYGWIN32__)
    return 0;  /* avoid the compiler complains about missing return value */
# endif
}

/*
 * If the X11 connection was lost try to restore it.
 * Helps when the X11 server was stopped and restarted while Vim was inactive
 * (e.g. through tmux).
 */
    static void
may_restore_clipboard(void)
{
    // No point in restoring the connecting if we are exiting or dying.
    if (!exiting && !v_dying && xterm_dpy_retry_count > 0)
    {
	--xterm_dpy_retry_count;

# ifndef LESSTIF_VERSION
	/* This has been reported to avoid Vim getting stuck. */
	if (app_context != (XtAppContext)NULL)
	{
	    XtDestroyApplicationContext(app_context);
	    app_context = (XtAppContext)NULL;
	    x11_display = NULL; /* freed by XtDestroyApplicationContext() */
	}
# endif

	setup_term_clip();
	get_x11_title(FALSE);
    }
}
#endif

/*
 * Test if "dpy" and x11_window are valid by getting the window title.
 * I don't actually want it yet, so there may be a simpler call to use, but
 * this will cause the error handler x_error_check() to be called if anything
 * is wrong, such as the window pointer being invalid (as can happen when the
 * user changes his DISPLAY, but not his WINDOWID) -- webb
 */
    static int
test_x11_window(Display *dpy)
{
    int			(*old_handler)();
    XTextProperty	text_prop;

    old_handler = XSetErrorHandler(x_error_check);
    got_x_error = FALSE;
    if (XGetWMName(dpy, x11_window, &text_prop))
	XFree((void *)text_prop.value);
    XSync(dpy, False);
    (void)XSetErrorHandler(old_handler);

    if (p_verbose > 0 && got_x_error)
	verb_msg(_("Testing the X display failed"));

    return (got_x_error ? FAIL : OK);
}
#endif

#ifdef FEAT_TITLE

#ifdef FEAT_X11

static int get_x11_thing(int get_title, int test_only);

/*
 * try to get x11 window and display
 *
 * return FAIL for failure, OK otherwise
 */
    static int
get_x11_windis(void)
{
    char	    *winid;
    static int	    result = -1;
#define XD_NONE	 0	/* x11_display not set here */
#define XD_HERE	 1	/* x11_display opened here */
#define XD_GUI	 2	/* x11_display used from gui.dpy */
#define XD_XTERM 3	/* x11_display used from xterm_dpy */
    static int	    x11_display_from = XD_NONE;
    static int	    did_set_error_handler = FALSE;

    if (!did_set_error_handler)
    {
	/* X just exits if it finds an error otherwise! */
	(void)XSetErrorHandler(x_error_handler);
	did_set_error_handler = TRUE;
    }

#if defined(FEAT_GUI_X11) || defined(FEAT_GUI_GTK)
    if (gui.in_use)
    {
	/*
	 * If the X11 display was opened here before, for the window where Vim
	 * was started, close that one now to avoid a memory leak.
	 */
	if (x11_display_from == XD_HERE && x11_display != NULL)
	{
	    XCloseDisplay(x11_display);
	    x11_display_from = XD_NONE;
	}
	if (gui_get_x11_windis(&x11_window, &x11_display) == OK)
	{
	    x11_display_from = XD_GUI;
	    return OK;
	}
	x11_display = NULL;
	return FAIL;
    }
    else if (x11_display_from == XD_GUI)
    {
	/* GUI must have stopped somehow, clear x11_display */
	x11_window = 0;
	x11_display = NULL;
	x11_display_from = XD_NONE;
    }
#endif

    /* When started with the "-X" argument, don't try connecting. */
    if (!x_connect_to_server())
	return FAIL;

    /*
     * If WINDOWID not set, should try another method to find out
     * what the current window number is. The only code I know for
     * this is very complicated.
     * We assume that zero is invalid for WINDOWID.
     */
    if (x11_window == 0 && (winid = getenv("WINDOWID")) != NULL)
	x11_window = (Window)atol(winid);

#ifdef FEAT_XCLIPBOARD
    if (xterm_dpy != NULL && x11_window != 0)
    {
	/* We may have checked it already, but Gnome terminal can move us to
	 * another window, so we need to check every time. */
	if (x11_display_from != XD_XTERM)
	{
	    /*
	     * If the X11 display was opened here before, for the window where
	     * Vim was started, close that one now to avoid a memory leak.
	     */
	    if (x11_display_from == XD_HERE && x11_display != NULL)
		XCloseDisplay(x11_display);
	    x11_display = xterm_dpy;
	    x11_display_from = XD_XTERM;
	}
	if (test_x11_window(x11_display) == FAIL)
	{
	    /* probably bad $WINDOWID */
	    x11_window = 0;
	    x11_display = NULL;
	    x11_display_from = XD_NONE;
	    return FAIL;
	}
	return OK;
    }
#endif

    if (x11_window == 0 || x11_display == NULL)
	result = -1;

    if (result != -1)	    /* Have already been here and set this */
	return result;	    /* Don't do all these X calls again */

    if (x11_window != 0 && x11_display == NULL)
    {
#ifdef SET_SIG_ALARM
	RETSIGTYPE (*sig_save)();
#endif
#ifdef ELAPSED_FUNC
	elapsed_T start_tv;

	if (p_verbose > 0)
	    ELAPSED_INIT(start_tv);
#endif

#ifdef SET_SIG_ALARM
	/*
	 * Opening the Display may hang if the DISPLAY setting is wrong, or
	 * the network connection is bad.  Set an alarm timer to get out.
	 */
	sig_alarm_called = FALSE;
	sig_save = (RETSIGTYPE (*)())signal(SIGALRM,
						 (RETSIGTYPE (*)())sig_alarm);
	alarm(2);
#endif
	x11_display = XOpenDisplay(NULL);

#ifdef SET_SIG_ALARM
	alarm(0);
	signal(SIGALRM, (RETSIGTYPE (*)())sig_save);
	if (p_verbose > 0 && sig_alarm_called)
	    verb_msg((char_u *)_("Opening the X display timed out"));
#endif
	if (x11_display != NULL)
	{
# ifdef ELAPSED_FUNC
	    if (p_verbose > 0)
	    {
		verbose_enter();
		xopen_message(ELAPSED_FUNC(start_tv));
		verbose_leave();
	    }
# endif
	    if (test_x11_window(x11_display) == FAIL)
	    {
		/* Maybe window id is bad */
		x11_window = 0;
		XCloseDisplay(x11_display);
		x11_display = NULL;
	    }
	    else
		x11_display_from = XD_HERE;
	}
    }
    if (x11_window == 0 || x11_display == NULL)
	return (result = FAIL);

# ifdef FEAT_EVAL
    set_vim_var_nr(VV_WINDOWID, (long)x11_window);
# endif

    return (result = OK);
}

/*
 * Determine original x11 Window Title
 */
    static int
get_x11_title(int test_only)
{
    return get_x11_thing(TRUE, test_only);
}

/*
 * Determine original x11 Window icon
 */
    static int
get_x11_icon(int test_only)
{
    int		retval = FALSE;

    retval = get_x11_thing(FALSE, test_only);

    /* could not get old icon, use terminal name */
    if (oldicon == NULL && !test_only)
    {
	if (STRNCMP(T_NAME, "builtin_", 8) == 0)
	    oldicon = vim_strsave(T_NAME + 8);
	else
	    oldicon = vim_strsave(T_NAME);
    }

    return retval;
}

    static int
get_x11_thing(
    int		get_title,	/* get title string */
    int		test_only)
{
    XTextProperty	text_prop;
    int			retval = FALSE;
    Status		status;

    if (get_x11_windis() == OK)
    {
	/* Get window/icon name if any */
	if (get_title)
	    status = XGetWMName(x11_display, x11_window, &text_prop);
	else
	    status = XGetWMIconName(x11_display, x11_window, &text_prop);

	/*
	 * If terminal is xterm, then x11_window may be a child window of the
	 * outer xterm window that actually contains the window/icon name, so
	 * keep traversing up the tree until a window with a title/icon is
	 * found.
	 */
	/* Previously this was only done for xterm and alikes.  I don't see a
	 * reason why it would fail for other terminal emulators.
	 * if (term_is_xterm) */
	{
	    Window	    root;
	    Window	    parent;
	    Window	    win = x11_window;
	    Window	   *children;
	    unsigned int    num_children;

	    while (!status || text_prop.value == NULL)
	    {
		if (!XQueryTree(x11_display, win, &root, &parent, &children,
							       &num_children))
		    break;
		if (children)
		    XFree((void *)children);
		if (parent == root || parent == 0)
		    break;

		win = parent;
		if (get_title)
		    status = XGetWMName(x11_display, win, &text_prop);
		else
		    status = XGetWMIconName(x11_display, win, &text_prop);
	    }
	}
	if (status && text_prop.value != NULL)
	{
	    retval = TRUE;
	    if (!test_only)
	    {
#if defined(FEAT_XFONTSET) || defined(FEAT_MBYTE)
		if (text_prop.encoding == XA_STRING
# ifdef FEAT_MBYTE
			&& !has_mbyte
# endif
			)
		{
#endif
		    if (get_title)
			oldtitle = vim_strsave((char_u *)text_prop.value);
		    else
			oldicon = vim_strsave((char_u *)text_prop.value);
#if defined(FEAT_XFONTSET) || defined(FEAT_MBYTE)
		}
		else
		{
		    char    **cl;
		    Status  transform_status;
		    int	    n = 0;

		    transform_status = XmbTextPropertyToTextList(x11_display,
								 &text_prop,
								 &cl, &n);
		    if (transform_status >= Success && n > 0 && cl[0])
		    {
			if (get_title)
			    oldtitle = vim_strsave((char_u *) cl[0]);
			else
			    oldicon = vim_strsave((char_u *) cl[0]);
			XFreeStringList(cl);
		    }
		    else
		    {
			if (get_title)
			    oldtitle = vim_strsave((char_u *)text_prop.value);
			else
			    oldicon = vim_strsave((char_u *)text_prop.value);
		    }
		}
#endif
	    }
	    XFree((void *)text_prop.value);
	}
    }
    return retval;
}

/* Xutf8 functions are not avaialble on older systems. Note that on some
 * systems X_HAVE_UTF8_STRING may be defined in a header file but
 * Xutf8SetWMProperties() is not in the X11 library.  Configure checks for
 * that and defines HAVE_XUTF8SETWMPROPERTIES. */
#if defined(X_HAVE_UTF8_STRING) && defined(FEAT_MBYTE)
# if X_HAVE_UTF8_STRING && HAVE_XUTF8SETWMPROPERTIES
#  define USE_UTF8_STRING
# endif
#endif

/*
 * Set x11 Window Title
 *
 * get_x11_windis() must be called before this and have returned OK
 */
    static void
set_x11_title(char_u *title)
{
	/* XmbSetWMProperties() and Xutf8SetWMProperties() should use a STRING
	 * when possible, COMPOUND_TEXT otherwise.  COMPOUND_TEXT isn't
	 * supported everywhere and STRING doesn't work for multi-byte titles.
	 */
#ifdef USE_UTF8_STRING
    if (enc_utf8)
	Xutf8SetWMProperties(x11_display, x11_window, (const char *)title,
					     NULL, NULL, 0, NULL, NULL, NULL);
    else
#endif
    {
#if XtSpecificationRelease >= 4
# ifdef FEAT_XFONTSET
	XmbSetWMProperties(x11_display, x11_window, (const char *)title,
					     NULL, NULL, 0, NULL, NULL, NULL);
# else
	XTextProperty	text_prop;
	char		*c_title = (char *)title;

	/* directly from example 3-18 "basicwin" of Xlib Programming Manual */
	(void)XStringListToTextProperty(&c_title, 1, &text_prop);
	XSetWMProperties(x11_display, x11_window, &text_prop,
					     NULL, NULL, 0, NULL, NULL, NULL);
# endif
#else
	XStoreName(x11_display, x11_window, (char *)title);
#endif
    }
    XFlush(x11_display);
}

/*
 * Set x11 Window icon
 *
 * get_x11_windis() must be called before this and have returned OK
 */
    static void
set_x11_icon(char_u *icon)
{
    /* See above for comments about using X*SetWMProperties(). */
#ifdef USE_UTF8_STRING
    if (enc_utf8)
	Xutf8SetWMProperties(x11_display, x11_window, NULL, (const char *)icon,
						   NULL, 0, NULL, NULL, NULL);
    else
#endif
    {
#if XtSpecificationRelease >= 4
# ifdef FEAT_XFONTSET
	XmbSetWMProperties(x11_display, x11_window, NULL, (const char *)icon,
						   NULL, 0, NULL, NULL, NULL);
# else
	XTextProperty	text_prop;
	char		*c_icon = (char *)icon;

	(void)XStringListToTextProperty(&c_icon, 1, &text_prop);
	XSetWMProperties(x11_display, x11_window, NULL, &text_prop,
						   NULL, 0, NULL, NULL, NULL);
# endif
#else
	XSetIconName(x11_display, x11_window, (char *)icon);
#endif
    }
    XFlush(x11_display);
}

#else  /* FEAT_X11 */

    static int
get_x11_title(int test_only UNUSED)
{
    return FALSE;
}

    static int
get_x11_icon(int test_only)
{
    if (!test_only)
    {
	if (STRNCMP(T_NAME, "builtin_", 8) == 0)
	    oldicon = vim_strsave(T_NAME + 8);
	else
	    oldicon = vim_strsave(T_NAME);
    }
    return FALSE;
}

#endif /* FEAT_X11 */

    int
mch_can_restore_title(void)
{
    return get_x11_title(TRUE);
}

    int
mch_can_restore_icon(void)
{
    return get_x11_icon(TRUE);
}

/*
 * Set the window title and icon.
 */
    void
mch_settitle(char_u *title, char_u *icon)
{
    int		type = 0;
    static int	recursive = 0;

    if (T_NAME == NULL)	    /* no terminal name (yet) */
	return;
    if (title == NULL && icon == NULL)	    /* nothing to do */
	return;

    /* When one of the X11 functions causes a deadly signal, we get here again
     * recursively.  Avoid hanging then (something is probably locked). */
    if (recursive)
	return;
    ++recursive;

    /*
     * if the window ID and the display is known, we may use X11 calls
     */
#ifdef FEAT_X11
    if (get_x11_windis() == OK)
	type = 1;
#else
# if defined(FEAT_GUI_PHOTON) || defined(FEAT_GUI_MAC) || defined(FEAT_GUI_GTK)
    if (gui.in_use)
	type = 1;
# endif
#endif

    /*
     * Note: if "t_ts" is set, title is set with escape sequence rather
     *	     than x11 calls, because the x11 calls don't always work
     */
    if ((type || *T_TS != NUL) && title != NULL)
    {
	if (oldtitle_outdated)
	{
	    oldtitle_outdated = FALSE;
	    VIM_CLEAR(oldtitle);
	}
	if (oldtitle == NULL
#ifdef FEAT_GUI
		&& !gui.in_use
#endif
		)		/* first call but not in GUI, save title */
	    (void)get_x11_title(FALSE);

	if (*T_TS != NUL)		/* it's OK if t_fs is empty */
	    term_settitle(title);
#ifdef FEAT_X11
	else
# ifdef FEAT_GUI_GTK
	if (!gui.in_use)		/* don't do this if GTK+ is running */
# endif
	    set_x11_title(title);		/* x11 */
#endif
#if defined(FEAT_GUI_GTK) \
	|| defined(FEAT_GUI_PHOTON) || defined(FEAT_GUI_MAC)
	else
	    gui_mch_settitle(title, icon);
#endif
	did_set_title = TRUE;
    }

    if ((type || *T_CIS != NUL) && icon != NULL)
    {
	if (oldicon == NULL
#ifdef FEAT_GUI
		&& !gui.in_use
#endif
		)		/* first call, save icon */
	    get_x11_icon(FALSE);

	if (*T_CIS != NUL)
	{
	    out_str(T_CIS);			/* set icon start */
	    out_str_nf(icon);
	    out_str(T_CIE);			/* set icon end */
	    out_flush();
	}
#ifdef FEAT_X11
	else
# ifdef FEAT_GUI_GTK
	if (!gui.in_use)		/* don't do this if GTK+ is running */
# endif
	    set_x11_icon(icon);			/* x11 */
#endif
	did_set_icon = TRUE;
    }
    --recursive;
}

/*
 * Restore the window/icon title.
 * "which" is one of:
 *  SAVE_RESTORE_TITLE only restore title
 *  SAVE_RESTORE_ICON  only restore icon
 *  SAVE_RESTORE_BOTH  restore title and icon
 */
    void
mch_restore_title(int which)
{
    /* only restore the title or icon when it has been set */
    mch_settitle(((which & SAVE_RESTORE_TITLE) && did_set_title) ?
			(oldtitle ? oldtitle : p_titleold) : NULL,
	       ((which & SAVE_RESTORE_ICON) && did_set_icon) ? oldicon : NULL);

    // pop and push from/to the stack
    term_pop_title(which);
    term_push_title(which);
}

#endif /* FEAT_TITLE */

/*
 * Return TRUE if "name" looks like some xterm name.
 * Seiichi Sato mentioned that "mlterm" works like xterm.
 */
    int
vim_is_xterm(char_u *name)
{
    if (name == NULL)
	return FALSE;
    return (STRNICMP(name, "xterm", 5) == 0
		|| STRNICMP(name, "nxterm", 6) == 0
		|| STRNICMP(name, "kterm", 5) == 0
		|| STRNICMP(name, "mlterm", 6) == 0
		|| STRNICMP(name, "rxvt", 4) == 0
		|| STRNICMP(name, "screen.xterm", 12) == 0
		|| STRCMP(name, "builtin_xterm") == 0);
}

#if defined(FEAT_MOUSE_XTERM) || defined(PROTO)
/*
 * Return TRUE if "name" appears to be that of a terminal
 * known to support the xterm-style mouse protocol.
 * Relies on term_is_xterm having been set to its correct value.
 */
    int
use_xterm_like_mouse(char_u *name)
{
    return (name != NULL
	    && (term_is_xterm
		|| STRNICMP(name, "screen", 6) == 0
		|| STRNICMP(name, "tmux", 4) == 0
		|| STRICMP(name, "st") == 0
		|| STRNICMP(name, "st-", 3) == 0
		|| STRNICMP(name, "stterm", 6) == 0));
}
#endif

#if defined(FEAT_MOUSE_TTY) || defined(PROTO)
/*
 * Return non-zero when using an xterm mouse, according to 'ttymouse'.
 * Return 1 for "xterm".
 * Return 2 for "xterm2".
 * Return 3 for "urxvt".
 * Return 4 for "sgr".
 */
    int
use_xterm_mouse(void)
{
    if (ttym_flags == TTYM_SGR)
	return 4;
    if (ttym_flags == TTYM_URXVT)
	return 3;
    if (ttym_flags == TTYM_XTERM2)
	return 2;
    if (ttym_flags == TTYM_XTERM)
	return 1;
    return 0;
}
#endif

    int
vim_is_iris(char_u *name)
{
    if (name == NULL)
	return FALSE;
    return (STRNICMP(name, "iris-ansi", 9) == 0
	    || STRCMP(name, "builtin_iris-ansi") == 0);
}

    int
vim_is_vt300(char_u *name)
{
    if (name == NULL)
	return FALSE;	       /* actually all ANSI comp. terminals should be here  */
    /* catch VT100 - VT5xx */
    return ((STRNICMP(name, "vt", 2) == 0
		&& vim_strchr((char_u *)"12345", name[2]) != NULL)
	    || STRCMP(name, "builtin_vt320") == 0);
}

/*
 * Return TRUE if "name" is a terminal for which 'ttyfast' should be set.
 * This should include all windowed terminal emulators.
 */
    int
vim_is_fastterm(char_u *name)
{
    if (name == NULL)
	return FALSE;
    if (vim_is_xterm(name) || vim_is_vt300(name) || vim_is_iris(name))
	return TRUE;
    return (   STRNICMP(name, "hpterm", 6) == 0
	    || STRNICMP(name, "sun-cmd", 7) == 0
	    || STRNICMP(name, "screen", 6) == 0
	    || STRNICMP(name, "tmux", 4) == 0
	    || STRNICMP(name, "dtterm", 6) == 0);
}

/*
 * Insert user name in s[len].
 * Return OK if a name found.
 */
    int
mch_get_user_name(char_u *s, int len)
{
#ifdef VMS
    vim_strncpy(s, (char_u *)cuserid(NULL), len - 1);
    return OK;
#else
    return mch_get_uname(getuid(), s, len);
#endif
}

/*
 * Insert user name for "uid" in s[len].
 * Return OK if a name found.
 */
    int
mch_get_uname(uid_t uid, char_u *s, int len)
{
#if defined(HAVE_PWD_H) && defined(HAVE_GETPWUID)
    struct passwd   *pw;

    if ((pw = getpwuid(uid)) != NULL
	    && pw->pw_name != NULL && *(pw->pw_name) != NUL)
    {
	vim_strncpy(s, (char_u *)pw->pw_name, len - 1);
	return OK;
    }
#endif
    sprintf((char *)s, "%d", (int)uid);	    /* assumes s is long enough */
    return FAIL;			    /* a number is not a name */
}

/*
 * Insert host name is s[len].
 */

#ifdef HAVE_SYS_UTSNAME_H
    void
mch_get_host_name(char_u *s, int len)
{
    struct utsname vutsname;

    if (uname(&vutsname) < 0)
	*s = NUL;
    else
	vim_strncpy(s, (char_u *)vutsname.nodename, len - 1);
}
#else /* HAVE_SYS_UTSNAME_H */

# ifdef HAVE_SYS_SYSTEMINFO_H
#  define gethostname(nam, len) sysinfo(SI_HOSTNAME, nam, len)
# endif

    void
mch_get_host_name(char_u *s, int len)
{
# ifdef VAXC
    vaxc$gethostname((char *)s, len);
# else
    gethostname((char *)s, len);
# endif
    s[len - 1] = NUL;	/* make sure it's terminated */
}
#endif /* HAVE_SYS_UTSNAME_H */

/*
 * return process ID
 */
    long
mch_get_pid(void)
{
    return (long)getpid();
}

#if !defined(HAVE_STRERROR) && defined(USE_GETCWD)
    static char *
strerror(int err)
{
    extern int	    sys_nerr;
    extern char	    *sys_errlist[];
    static char	    er[20];

    if (err > 0 && err < sys_nerr)
	return (sys_errlist[err]);
    sprintf(er, "Error %d", err);
    return er;
}
#endif

/*
 * Get name of current directory into buffer 'buf' of length 'len' bytes.
 * Return OK for success, FAIL for failure.
 */
    int
mch_dirname(char_u *buf, int len)
{
#if defined(USE_GETCWD)
    if (getcwd((char *)buf, len) == NULL)
    {
	STRCPY(buf, strerror(errno));
	return FAIL;
    }
    return OK;
#else
    return (getwd((char *)buf) != NULL ? OK : FAIL);
#endif
}

/*
 * Get absolute file name into "buf[len]".
 *
 * return FAIL for failure, OK for success
 */
    int
mch_FullName(
    char_u	*fname,
    char_u	*buf,
    int		len,
    int		force)		/* also expand when already absolute path */
{
    int		l;
#ifdef HAVE_FCHDIR
    int		fd = -1;
    static int	dont_fchdir = FALSE;	/* TRUE when fchdir() doesn't work */
#endif
    char_u	olddir[MAXPATHL];
    char_u	*p;
    int		retval = OK;
#ifdef __CYGWIN__
    char_u	posix_fname[MAXPATHL];	/* Cygwin docs mention MAX_PATH, but
					   it's not always defined */
#endif

#ifdef VMS
    fname = vms_fixfilename(fname);
#endif

#ifdef __CYGWIN__
    /*
     * This helps for when "/etc/hosts" is a symlink to "c:/something/hosts".
     */
# if CYGWIN_VERSION_DLL_MAJOR >= 1007
    /* Use CCP_RELATIVE to avoid that it sometimes returns a path that ends in
     * a forward slash. */
    cygwin_conv_path(CCP_WIN_A_TO_POSIX | CCP_RELATIVE,
		     fname, posix_fname, MAXPATHL);
# else
    cygwin_conv_to_posix_path(fname, posix_fname);
# endif
    fname = posix_fname;
#endif

    /* Expand it if forced or not an absolute path.
     * Do not do it for "/file", the result is always "/". */
    if ((force || !mch_isFullName(fname))
	    && ((p = vim_strrchr(fname, '/')) == NULL || p != fname))
    {
	/*
	 * If the file name has a path, change to that directory for a moment,
	 * and then do the getwd() (and get back to where we were).
	 * This will get the correct path name with "../" things.
	 */
	if (p != NULL)
	{
#ifdef HAVE_FCHDIR
	    /*
	     * Use fchdir() if possible, it's said to be faster and more
	     * reliable.  But on SunOS 4 it might not work.  Check this by
	     * doing a fchdir() right now.
	     */
	    if (!dont_fchdir)
	    {
		fd = open(".", O_RDONLY | O_EXTRA, 0);
		if (fd >= 0 && fchdir(fd) < 0)
		{
		    close(fd);
		    fd = -1;
		    dont_fchdir = TRUE;	    /* don't try again */
		}
	    }
#endif

	    /* Only change directory when we are sure we can return to where
	     * we are now.  After doing "su" chdir(".") might not work. */
	    if (
#ifdef HAVE_FCHDIR
		fd < 0 &&
#endif
			(mch_dirname(olddir, MAXPATHL) == FAIL
					   || mch_chdir((char *)olddir) != 0))
	    {
		p = NULL;	/* can't get current dir: don't chdir */
		retval = FAIL;
	    }
	    else
	    {
		/* The directory is copied into buf[], to be able to remove
		 * the file name without changing it (could be a string in
		 * read-only memory) */
		if (p - fname >= len)
		    retval = FAIL;
		else
		{
		    vim_strncpy(buf, fname, p - fname);
		    if (mch_chdir((char *)buf))
			retval = FAIL;
		    else
			fname = p + 1;
		    *buf = NUL;
		}
	    }
	}
	if (mch_dirname(buf, len) == FAIL)
	{
	    retval = FAIL;
	    *buf = NUL;
	}
	if (p != NULL)
	{
#ifdef HAVE_FCHDIR
	    if (fd >= 0)
	    {
		if (p_verbose >= 5)
		{
		    verbose_enter();
		    msg("fchdir() to previous dir");
		    verbose_leave();
		}
		l = fchdir(fd);
		close(fd);
	    }
	    else
#endif
		l = mch_chdir((char *)olddir);
	    if (l != 0)
		emsg(_(e_prev_dir));
	}

	l = STRLEN(buf);
	if (l >= len - 1)
	    retval = FAIL; /* no space for trailing "/" */
#ifndef VMS
	else if (l > 0 && buf[l - 1] != '/' && *fname != NUL
						   && STRCMP(fname, ".") != 0)
	    STRCAT(buf, "/");
#endif
    }

    /* Catch file names which are too long. */
    if (retval == FAIL || (int)(STRLEN(buf) + STRLEN(fname)) >= len)
	return FAIL;

    /* Do not append ".", "/dir/." is equal to "/dir". */
    if (STRCMP(fname, ".") != 0)
	STRCAT(buf, fname);

    return OK;
}

/*
 * Return TRUE if "fname" does not depend on the current directory.
 */
    int
mch_isFullName(char_u *fname)
{
#ifdef VMS
    return ( fname[0] == '/'	       || fname[0] == '.'	    ||
	     strchr((char *)fname,':') || strchr((char *)fname,'"') ||
	    (strchr((char *)fname,'[') && strchr((char *)fname,']'))||
	    (strchr((char *)fname,'<') && strchr((char *)fname,'>'))   );
#else
    return (*fname == '/' || *fname == '~');
#endif
}

#if defined(USE_FNAME_CASE) || defined(PROTO)
/*
 * Set the case of the file name, if it already exists.  This will cause the
 * file name to remain exactly the same.
 * Only required for file systems where case is ignored and preserved.
 */
    void
fname_case(
    char_u	*name,
    int		len UNUSED)  /* buffer size, only used when name gets longer */
{
    struct stat st;
    char_u	*slash, *tail;
    DIR		*dirp;
    struct dirent *dp;

    if (mch_lstat((char *)name, &st) >= 0)
    {
	/* Open the directory where the file is located. */
	slash = vim_strrchr(name, '/');
	if (slash == NULL)
	{
	    dirp = opendir(".");
	    tail = name;
	}
	else
	{
	    *slash = NUL;
	    dirp = opendir((char *)name);
	    *slash = '/';
	    tail = slash + 1;
	}

	if (dirp != NULL)
	{
	    while ((dp = readdir(dirp)) != NULL)
	    {
		/* Only accept names that differ in case and are the same byte
		 * length. TODO: accept different length name. */
		if (STRICMP(tail, dp->d_name) == 0
			&& STRLEN(tail) == STRLEN(dp->d_name))
		{
		    char_u	newname[MAXPATHL + 1];
		    struct stat st2;

		    /* Verify the inode is equal. */
		    vim_strncpy(newname, name, MAXPATHL);
		    vim_strncpy(newname + (tail - name), (char_u *)dp->d_name,
						    MAXPATHL - (tail - name));
		    if (mch_lstat((char *)newname, &st2) >= 0
			    && st.st_ino == st2.st_ino
			    && st.st_dev == st2.st_dev)
		    {
			STRCPY(tail, dp->d_name);
			break;
		    }
		}
	    }

	    closedir(dirp);
	}
    }
}
#endif

/*
 * Get file permissions for 'name'.
 * Returns -1 when it doesn't exist.
 */
    long
mch_getperm(char_u *name)
{
    struct stat statb;

    /* Keep the #ifdef outside of stat(), it may be a macro. */
#ifdef VMS
    if (stat((char *)vms_fixfilename(name), &statb))
#else
    if (stat((char *)name, &statb))
#endif
	return -1;
#ifdef __INTERIX
    /* The top bit makes the value negative, which means the file doesn't
     * exist.  Remove the bit, we don't use it. */
    return statb.st_mode & ~S_ADDACE;
#else
    return statb.st_mode;
#endif
}

/*
 * Set file permission for "name" to "perm".
 * Return FAIL for failure, OK otherwise.
 */
    int
mch_setperm(char_u *name, long perm)
{
    return (chmod((char *)
#ifdef VMS
		    vms_fixfilename(name),
#else
		    name,
#endif
		    (mode_t)perm) == 0 ? OK : FAIL);
}

#if defined(HAVE_FCHMOD) || defined(PROTO)
/*
 * Set file permission for open file "fd" to "perm".
 * Return FAIL for failure, OK otherwise.
 */
    int
mch_fsetperm(int fd, long perm)
{
    return (fchmod(fd, (mode_t)perm) == 0 ? OK : FAIL);
}
#endif

#if defined(HAVE_ACL) || defined(PROTO)
# ifdef HAVE_SYS_ACL_H
#  include <sys/acl.h>
# endif
# ifdef HAVE_SYS_ACCESS_H
#  include <sys/access.h>
# endif

# ifdef HAVE_SOLARIS_ACL
typedef struct vim_acl_solaris_T {
    int acl_cnt;
    aclent_t *acl_entry;
} vim_acl_solaris_T;
# endif

#if defined(HAVE_SELINUX) || defined(PROTO)
/*
 * Copy security info from "from_file" to "to_file".
 */
    void
mch_copy_sec(char_u *from_file, char_u *to_file)
{
    if (from_file == NULL)
	return;

    if (selinux_enabled == -1)
	selinux_enabled = is_selinux_enabled();

    if (selinux_enabled > 0)
    {
	security_context_t from_context = NULL;
	security_context_t to_context = NULL;

	if (getfilecon((char *)from_file, &from_context) < 0)
	{
	    /* If the filesystem doesn't support extended attributes,
	       the original had no special security context and the
	       target cannot have one either.  */
	    if (errno == EOPNOTSUPP)
		return;

	    msg_puts(_("\nCould not get security context for "));
	    msg_outtrans(from_file);
	    msg_putchar('\n');
	    return;
	}
	if (getfilecon((char *)to_file, &to_context) < 0)
	{
	    msg_puts(_("\nCould not get security context for "));
	    msg_outtrans(to_file);
	    msg_putchar('\n');
	    freecon (from_context);
	    return ;
	}
	if (strcmp(from_context, to_context) != 0)
	{
	    if (setfilecon((char *)to_file, from_context) < 0)
	    {
		msg_puts(_("\nCould not set security context for "));
		msg_outtrans(to_file);
		msg_putchar('\n');
	    }
	}
	freecon(to_context);
	freecon(from_context);
    }
}
#endif /* HAVE_SELINUX */

#if defined(HAVE_SMACK) && !defined(PROTO)
/*
 * Copy security info from "from_file" to "to_file".
 */
    void
mch_copy_sec(char_u *from_file, char_u *to_file)
{
    static const char * const smack_copied_attributes[] =
	{
	    XATTR_NAME_SMACK,
	    XATTR_NAME_SMACKEXEC,
	    XATTR_NAME_SMACKMMAP
	};

    char	buffer[SMACK_LABEL_LEN];
    const char	*name;
    int		index;
    int		ret;
    ssize_t	size;

    if (from_file == NULL)
	return;

    for (index = 0 ; index < (int)(sizeof(smack_copied_attributes)
			      / sizeof(smack_copied_attributes)[0]) ; index++)
    {
	/* get the name of the attribute to copy */
	name = smack_copied_attributes[index];

	/* get the value of the attribute in buffer */
	size = getxattr((char*)from_file, name, buffer, sizeof(buffer));
	if (size >= 0)
	{
	    /* copy the attribute value of buffer */
	    ret = setxattr((char*)to_file, name, buffer, (size_t)size, 0);
	    if (ret < 0)
	    {
		vim_snprintf((char *)IObuff, IOSIZE,
			_("Could not set security context %s for %s"),
			name, to_file);
		msg_outtrans(IObuff);
		msg_putchar('\n');
	    }
	}
	else
	{
	    /* what reason of not having the attribute value? */
	    switch (errno)
	    {
		case ENOTSUP:
		    /* extended attributes aren't supported or enabled */
		    /* should a message be echoed? not sure... */
		    return; /* leave because it isn't usefull to continue */

		case ERANGE:
		default:
		    /* no enough size OR unexpected error */
		     vim_snprintf((char *)IObuff, IOSIZE,
			    _("Could not get security context %s for %s. Removing it!"),
			    name, from_file);
		    msg_puts((char *)IObuff);
		    msg_putchar('\n');
		    /* FALLTHROUGH to remove the attribute */

		case ENODATA:
		    /* no attribute of this name */
		    ret = removexattr((char*)to_file, name);
		    /* Silently ignore errors, apparently this happens when
		     * smack is not actually being used. */
		    break;
	    }
	}
    }
}
#endif /* HAVE_SMACK */

/*
 * Return a pointer to the ACL of file "fname" in allocated memory.
 * Return NULL if the ACL is not available for whatever reason.
 */
    vim_acl_T
mch_get_acl(char_u *fname UNUSED)
{
    vim_acl_T	ret = NULL;
#ifdef HAVE_POSIX_ACL
    ret = (vim_acl_T)acl_get_file((char *)fname, ACL_TYPE_ACCESS);
#else
#ifdef HAVE_SOLARIS_ZFS_ACL
    acl_t *aclent;

    if (acl_get((char *)fname, 0, &aclent) < 0)
	return NULL;
    ret = (vim_acl_T)aclent;
#else
#ifdef HAVE_SOLARIS_ACL
    vim_acl_solaris_T   *aclent;

    aclent = malloc(sizeof(vim_acl_solaris_T));
    if ((aclent->acl_cnt = acl((char *)fname, GETACLCNT, 0, NULL)) < 0)
    {
	free(aclent);
	return NULL;
    }
    aclent->acl_entry = malloc(aclent->acl_cnt * sizeof(aclent_t));
    if (acl((char *)fname, GETACL, aclent->acl_cnt, aclent->acl_entry) < 0)
    {
	free(aclent->acl_entry);
	free(aclent);
	return NULL;
    }
    ret = (vim_acl_T)aclent;
#else
#if defined(HAVE_AIX_ACL)
    int		aclsize;
    struct acl *aclent;

    aclsize = sizeof(struct acl);
    aclent = malloc(aclsize);
    if (statacl((char *)fname, STX_NORMAL, aclent, aclsize) < 0)
    {
	if (errno == ENOSPC)
	{
	    aclsize = aclent->acl_len;
	    aclent = realloc(aclent, aclsize);
	    if (statacl((char *)fname, STX_NORMAL, aclent, aclsize) < 0)
	    {
		free(aclent);
		return NULL;
	    }
	}
	else
	{
	    free(aclent);
	    return NULL;
	}
    }
    ret = (vim_acl_T)aclent;
#endif /* HAVE_AIX_ACL */
#endif /* HAVE_SOLARIS_ACL */
#endif /* HAVE_SOLARIS_ZFS_ACL */
#endif /* HAVE_POSIX_ACL */
    return ret;
}

/*
 * Set the ACL of file "fname" to "acl" (unless it's NULL).
 */
    void
mch_set_acl(char_u *fname UNUSED, vim_acl_T aclent)
{
    if (aclent == NULL)
	return;
#ifdef HAVE_POSIX_ACL
    acl_set_file((char *)fname, ACL_TYPE_ACCESS, (acl_t)aclent);
#else
#ifdef HAVE_SOLARIS_ZFS_ACL
    acl_set((char *)fname, (acl_t *)aclent);
#else
#ifdef HAVE_SOLARIS_ACL
    acl((char *)fname, SETACL, ((vim_acl_solaris_T *)aclent)->acl_cnt,
	    ((vim_acl_solaris_T *)aclent)->acl_entry);
#else
#ifdef HAVE_AIX_ACL
    chacl((char *)fname, aclent, ((struct acl *)aclent)->acl_len);
#endif /* HAVE_AIX_ACL */
#endif /* HAVE_SOLARIS_ACL */
#endif /* HAVE_SOLARIS_ZFS_ACL */
#endif /* HAVE_POSIX_ACL */
}

    void
mch_free_acl(vim_acl_T aclent)
{
    if (aclent == NULL)
	return;
#ifdef HAVE_POSIX_ACL
    acl_free((acl_t)aclent);
#else
#ifdef HAVE_SOLARIS_ZFS_ACL
    acl_free((acl_t *)aclent);
#else
#ifdef HAVE_SOLARIS_ACL
    free(((vim_acl_solaris_T *)aclent)->acl_entry);
    free(aclent);
#else
#ifdef HAVE_AIX_ACL
    free(aclent);
#endif /* HAVE_AIX_ACL */
#endif /* HAVE_SOLARIS_ACL */
#endif /* HAVE_SOLARIS_ZFS_ACL */
#endif /* HAVE_POSIX_ACL */
}
#endif

/*
 * Set hidden flag for "name".
 */
    void
mch_hide(char_u *name UNUSED)
{
    /* can't hide a file */
}

/*
 * return TRUE if "name" is a directory or a symlink to a directory
 * return FALSE if "name" is not a directory
 * return FALSE for error
 */
    int
mch_isdir(char_u *name)
{
    struct stat statb;

    if (*name == NUL)	    /* Some stat()s don't flag "" as an error. */
	return FALSE;
    if (stat((char *)name, &statb))
	return FALSE;
    return (S_ISDIR(statb.st_mode) ? TRUE : FALSE);
}

/*
 * return TRUE if "name" is a directory, NOT a symlink to a directory
 * return FALSE if "name" is not a directory
 * return FALSE for error
 */
    int
mch_isrealdir(char_u *name)
{
    struct stat statb;

    if (*name == NUL)	    /* Some stat()s don't flag "" as an error. */
	return FALSE;
    if (mch_lstat((char *)name, &statb))
	return FALSE;
    return (S_ISDIR(statb.st_mode) ? TRUE : FALSE);
}

/*
 * Return 1 if "name" is an executable file, 0 if not or it doesn't exist.
 */
    static int
executable_file(char_u *name)
{
    struct stat	st;

    if (stat((char *)name, &st))
	return 0;
#ifdef VMS
    /* Like on Unix system file can have executable rights but not necessarily
     * be an executable, but on Unix is not a default for an ordianry file to
     * have an executable flag - on VMS it is in most cases.
     * Therefore, this check does not have any sense - let keep us to the
     * conventions instead:
     * *.COM and *.EXE files are the executables - the rest are not. This is
     * not ideal but better then it was.
     */
    int vms_executable = 0;
    if (S_ISREG(st.st_mode) && mch_access((char *)name, X_OK) == 0)
    {
	if (strstr(vms_tolower((char*)name),".exe") != NULL
		|| strstr(vms_tolower((char*)name),".com")!= NULL)
	    vms_executable = 1;
    }
    return vms_executable;
#else
    return S_ISREG(st.st_mode) && mch_access((char *)name, X_OK) == 0;
#endif
}

/*
 * Return TRUE if "name" can be found in $PATH and executed, FALSE if not.
 * If "use_path" is FALSE only check if "name" is executable.
 * Return -1 if unknown.
 */
    int
mch_can_exe(char_u *name, char_u **path, int use_path)
{
    char_u	*buf;
    char_u	*p, *e;
    int		retval;

    /* When "use_path" is false and if it's an absolute or relative path don't
     * need to use $PATH. */
    if (!use_path || mch_isFullName(name) || (name[0] == '.'
		   && (name[1] == '/' || (name[1] == '.' && name[2] == '/'))))
    {
	/* There must be a path separator, files in the current directory
	 * can't be executed. */
	if (gettail(name) != name && executable_file(name))
	{
	    if (path != NULL)
	    {
		if (name[0] != '/')
		    *path = FullName_save(name, TRUE);
		else
		    *path = vim_strsave(name);
	    }
	    return TRUE;
	}
	return FALSE;
    }

    p = (char_u *)getenv("PATH");
    if (p == NULL || *p == NUL)
	return -1;
    buf = alloc((unsigned)(STRLEN(name) + STRLEN(p) + 2));
    if (buf == NULL)
	return -1;

    /*
     * Walk through all entries in $PATH to check if "name" exists there and
     * is an executable file.
     */
    for (;;)
    {
	e = (char_u *)strchr((char *)p, ':');
	if (e == NULL)
	    e = p + STRLEN(p);
	if (e - p <= 1)		/* empty entry means current dir */
	    STRCPY(buf, "./");
	else
	{
	    vim_strncpy(buf, p, e - p);
	    add_pathsep(buf);
	}
	STRCAT(buf, name);
	retval = executable_file(buf);
	if (retval == 1)
	{
	    if (path != NULL)
	    {
		if (buf[0] != '/')
		    *path = FullName_save(buf, TRUE);
		else
		    *path = vim_strsave(buf);
	    }
	    break;
	}

	if (*e != ':')
	    break;
	p = e + 1;
    }

    vim_free(buf);
    return retval;
}

/*
 * Check what "name" is:
 * NODE_NORMAL: file or directory (or doesn't exist)
 * NODE_WRITABLE: writable device, socket, fifo, etc.
 * NODE_OTHER: non-writable things
 */
    int
mch_nodetype(char_u *name)
{
    struct stat	st;

    if (stat((char *)name, &st))
	return NODE_NORMAL;
    if (S_ISREG(st.st_mode) || S_ISDIR(st.st_mode))
	return NODE_NORMAL;
    if (S_ISBLK(st.st_mode))	/* block device isn't writable */
	return NODE_OTHER;
    /* Everything else is writable? */
    return NODE_WRITABLE;
}

    void
mch_early_init(void)
{
#ifdef HAVE_CHECK_STACK_GROWTH
    int			i;

    check_stack_growth((char *)&i);

# ifdef HAVE_STACK_LIMIT
    get_stack_limit();
# endif

#endif

    /*
     * Setup an alternative stack for signals.  Helps to catch signals when
     * running out of stack space.
     * Use of sigaltstack() is preferred, it's more portable.
     * Ignore any errors.
     */
#if defined(HAVE_SIGALTSTACK) || defined(HAVE_SIGSTACK)
    signal_stack = (char *)alloc(SIGSTKSZ);
    init_signal_stack();
#endif
}

#if defined(EXITFREE) || defined(PROTO)
    void
mch_free_mem(void)
{
# if defined(FEAT_CLIPBOARD) && defined(FEAT_X11)
    if (clip_star.owned)
	clip_lose_selection(&clip_star);
    if (clip_plus.owned)
	clip_lose_selection(&clip_plus);
# endif
# if defined(FEAT_X11) && defined(FEAT_XCLIPBOARD)
    if (xterm_Shell != (Widget)0)
	XtDestroyWidget(xterm_Shell);
#  ifndef LESSTIF_VERSION
    /* Lesstif crashes here, lose some memory */
    if (xterm_dpy != NULL)
	XtCloseDisplay(xterm_dpy);
    if (app_context != (XtAppContext)NULL)
    {
	XtDestroyApplicationContext(app_context);
#   ifdef FEAT_X11
	x11_display = NULL; /* freed by XtDestroyApplicationContext() */
#   endif
    }
#  endif
# endif
# if defined(FEAT_X11)
    if (x11_display != NULL
#  ifdef FEAT_XCLIPBOARD
	    && x11_display != xterm_dpy
#  endif
	    )
	XCloseDisplay(x11_display);
# endif
# if defined(HAVE_SIGALTSTACK) || defined(HAVE_SIGSTACK)
    VIM_CLEAR(signal_stack);
# endif
# ifdef FEAT_TITLE
    vim_free(oldtitle);
    vim_free(oldicon);
# endif
}
#endif

/*
 * Output a newline when exiting.
 * Make sure the newline goes to the same stream as the text.
 */
    static void
exit_scroll(void)
{
    if (silent_mode)
	return;
    if (newline_on_exit || msg_didout)
    {
	if (msg_use_printf())
	{
	    if (info_message)
		mch_msg("\n");
	    else
		mch_errmsg("\r\n");
	}
	else
	    out_char('\n');
    }
    else
    {
	restore_cterm_colors();		/* get original colors back */
	msg_clr_eos_force();		/* clear the rest of the display */
	windgoto((int)Rows - 1, 0);	/* may have moved the cursor */
    }
}

    void
mch_exit(int r)
{
    exiting = TRUE;

#if defined(FEAT_X11) && defined(FEAT_CLIPBOARD)
    x11_export_final_selection();
#endif

#ifdef FEAT_GUI
    if (!gui.in_use)
#endif
    {
	settmode(TMODE_COOK);
#ifdef FEAT_TITLE
	// restore xterm title and icon name
	mch_restore_title(SAVE_RESTORE_BOTH);
	term_pop_title(SAVE_RESTORE_BOTH);
#endif
	/*
	 * When t_ti is not empty but it doesn't cause swapping terminal
	 * pages, need to output a newline when msg_didout is set.  But when
	 * t_ti does swap pages it should not go to the shell page.  Do this
	 * before stoptermcap().
	 */
	if (swapping_screen() && !newline_on_exit)
	    exit_scroll();

	/* Stop termcap: May need to check for T_CRV response, which
	 * requires RAW mode. */
	stoptermcap();

	/*
	 * A newline is only required after a message in the alternate screen.
	 * This is set to TRUE by wait_return().
	 */
	if (!swapping_screen() || newline_on_exit)
	    exit_scroll();

	/* Cursor may have been switched off without calling starttermcap()
	 * when doing "vim -u vimrc" and vimrc contains ":q". */
	if (full_screen)
	    cursor_on();
    }
    out_flush();
    ml_close_all(TRUE);		/* remove all memfiles */
    may_core_dump();
#ifdef FEAT_GUI
    if (gui.in_use)
	gui_exit(r);
#endif

#ifdef MACOS_CONVERT
    mac_conv_cleanup();
#endif

#ifdef __QNX__
    /* A core dump won't be created if the signal handler
     * doesn't return, so we can't call exit() */
    if (deadly_signal != 0)
	return;
#endif

#ifdef FEAT_NETBEANS_INTG
    netbeans_send_disconnect();
#endif

#ifdef EXITFREE
    free_all_mem();
#endif

    exit(r);
}

    static void
may_core_dump(void)
{
    if (deadly_signal != 0)
    {
	signal(deadly_signal, SIG_DFL);
	kill(getpid(), deadly_signal);	/* Die using the signal we caught */
    }
}

#ifndef VMS

    void
mch_settmode(int tmode)
{
    static int first = TRUE;

#ifdef NEW_TTY_SYSTEM
# ifdef HAVE_TERMIOS_H
    static struct termios told;
	   struct termios tnew;
# else
    static struct termio told;
	   struct termio tnew;
# endif

    if (first)
    {
	first = FALSE;
# if defined(HAVE_TERMIOS_H)
	tcgetattr(read_cmd_fd, &told);
# else
	ioctl(read_cmd_fd, TCGETA, &told);
# endif
    }

    tnew = told;
    if (tmode == TMODE_RAW)
    {
	/*
	 * ~ICRNL enables typing ^V^M
	 */
	tnew.c_iflag &= ~ICRNL;
	tnew.c_lflag &= ~(ICANON | ECHO | ISIG | ECHOE
# if defined(IEXTEN) && !defined(__MINT__)
		    | IEXTEN	    /* IEXTEN enables typing ^V on SOLARIS */
				    /* but it breaks function keys on MINT */
# endif
				);
# ifdef ONLCR	    /* don't map NL -> CR NL, we do it ourselves */
	tnew.c_oflag &= ~ONLCR;
# endif
	tnew.c_cc[VMIN] = 1;		/* return after 1 char */
	tnew.c_cc[VTIME] = 0;		/* don't wait */
    }
    else if (tmode == TMODE_SLEEP)
    {
	/* Also reset ICANON here, otherwise on Solaris select() won't see
	 * typeahead characters. */
	tnew.c_lflag &= ~(ICANON | ECHO);
	tnew.c_cc[VMIN] = 1;		/* return after 1 char */
	tnew.c_cc[VTIME] = 0;		/* don't wait */
    }

# if defined(HAVE_TERMIOS_H)
    {
	int	n = 10;

	/* A signal may cause tcsetattr() to fail (e.g., SIGCONT).  Retry a
	 * few times. */
	while (tcsetattr(read_cmd_fd, TCSANOW, &tnew) == -1
						   && errno == EINTR && n > 0)
	    --n;
    }
# else
    ioctl(read_cmd_fd, TCSETA, &tnew);
# endif

#else
    /*
     * for "old" tty systems
     */
# ifndef TIOCSETN
#  define TIOCSETN TIOCSETP	/* for hpux 9.0 */
# endif
    static struct sgttyb ttybold;
	   struct sgttyb ttybnew;

    if (first)
    {
	first = FALSE;
	ioctl(read_cmd_fd, TIOCGETP, &ttybold);
    }

    ttybnew = ttybold;
    if (tmode == TMODE_RAW)
    {
	ttybnew.sg_flags &= ~(CRMOD | ECHO);
	ttybnew.sg_flags |= RAW;
    }
    else if (tmode == TMODE_SLEEP)
	ttybnew.sg_flags &= ~(ECHO);
    ioctl(read_cmd_fd, TIOCSETN, &ttybnew);
#endif
    curr_tmode = tmode;
}

/*
 * Try to get the code for "t_kb" from the stty setting
 *
 * Even if termcap claims a backspace key, the user's setting *should*
 * prevail.  stty knows more about reality than termcap does, and if
 * somebody's usual erase key is DEL (which, for most BSD users, it will
 * be), they're going to get really annoyed if their erase key starts
 * doing forward deletes for no reason. (Eric Fischer)
 */
    void
get_stty(void)
{
    ttyinfo_T	info;
    char_u	buf[2];
    char_u	*p;

    if (get_tty_info(read_cmd_fd, &info) == OK)
    {
	intr_char = info.interrupt;
	buf[0] = info.backspace;
	buf[1] = NUL;
	add_termcode((char_u *)"kb", buf, FALSE);

	/* If <BS> and <DEL> are now the same, redefine <DEL>. */
	p = find_termcode((char_u *)"kD");
	if (p != NULL && p[0] == buf[0] && p[1] == buf[1])
	    do_fixdel(NULL);
    }
}

/*
 * Obtain the characters that Backspace and Enter produce on "fd".
 * Returns OK or FAIL.
 */
    int
get_tty_info(int fd, ttyinfo_T *info)
{
#ifdef NEW_TTY_SYSTEM
# ifdef HAVE_TERMIOS_H
    struct termios keys;
# else
    struct termio keys;
# endif

    if (
# if defined(HAVE_TERMIOS_H)
	    tcgetattr(fd, &keys) != -1
# else
	    ioctl(fd, TCGETA, &keys) != -1
# endif
       )
    {
	info->backspace = keys.c_cc[VERASE];
	info->interrupt = keys.c_cc[VINTR];
	if (keys.c_iflag & ICRNL)
	    info->enter = NL;
	else
	    info->enter = CAR;
	if (keys.c_oflag & ONLCR)
	    info->nl_does_cr = TRUE;
	else
	    info->nl_does_cr = FALSE;
	return OK;
    }
#else
    /* for "old" tty systems */
    struct sgttyb keys;

    if (ioctl(fd, TIOCGETP, &keys) != -1)
    {
	info->backspace = keys.sg_erase;
	info->interrupt = keys.sg_kill;
	info->enter = CAR;
	info->nl_does_cr = TRUE;
	return OK;
    }
#endif
    return FAIL;
}

#endif /* VMS  */

#if defined(FEAT_MOUSE_TTY) || defined(PROTO)
static int	mouse_ison = FALSE;

/*
 * Set mouse clicks on or off.
 */
    void
mch_setmouse(int on)
{
# ifdef FEAT_BEVAL_TERM
    static int	bevalterm_ison = FALSE;
# endif
    int		xterm_mouse_vers;

# if defined(FEAT_X11) && defined(FEAT_XCLIPBOARD)
    if (!on)
	// Make sure not tracing mouse movements.  Important when a button-down
	// was received but no release yet.
	stop_xterm_trace();
# endif

    if (on == mouse_ison
# ifdef FEAT_BEVAL_TERM
	    && p_bevalterm == bevalterm_ison
# endif
	    )
	/* return quickly if nothing to do */
	return;

    xterm_mouse_vers = use_xterm_mouse();

# ifdef FEAT_MOUSE_URXVT
    if (ttym_flags == TTYM_URXVT)
    {
	out_str_nf((char_u *)
		   (on
		   ? IF_EB("\033[?1015h", ESC_STR "[?1015h")
		   : IF_EB("\033[?1015l", ESC_STR "[?1015l")));
	mouse_ison = on;
    }
# endif

# ifdef FEAT_MOUSE_SGR
    if (ttym_flags == TTYM_SGR)
    {
	/* SGR mode supports columns above 223 */
	out_str_nf((char_u *)
		   (on
		   ? IF_EB("\033[?1006h", ESC_STR "[?1006h")
		   : IF_EB("\033[?1006l", ESC_STR "[?1006l")));
	mouse_ison = on;
    }
# endif

# ifdef FEAT_BEVAL_TERM
    if (bevalterm_ison != (p_bevalterm && on))
    {
	bevalterm_ison = (p_bevalterm && on);
	if (xterm_mouse_vers > 1 && !bevalterm_ison)
	    /* disable mouse movement events, enabling is below */
	    out_str_nf((char_u *)
			(IF_EB("\033[?1003l", ESC_STR "[?1003l")));
    }
# endif

    if (xterm_mouse_vers > 0)
    {
	if (on)	/* enable mouse events, use mouse tracking if available */
	    out_str_nf((char_u *)
		       (xterm_mouse_vers > 1
			? (
# ifdef FEAT_BEVAL_TERM
			    bevalterm_ison
			       ? IF_EB("\033[?1003h", ESC_STR "[?1003h") :
# endif
			      IF_EB("\033[?1002h", ESC_STR "[?1002h"))
			: IF_EB("\033[?1000h", ESC_STR "[?1000h")));
	else	/* disable mouse events, could probably always send the same */
	    out_str_nf((char_u *)
		       (xterm_mouse_vers > 1
			? IF_EB("\033[?1002l", ESC_STR "[?1002l")
			: IF_EB("\033[?1000l", ESC_STR "[?1000l")));
	mouse_ison = on;
    }

# ifdef FEAT_MOUSE_DEC
    else if (ttym_flags == TTYM_DEC)
    {
	if (on)	/* enable mouse events */
	    out_str_nf((char_u *)"\033[1;2'z\033[1;3'{");
	else	/* disable mouse events */
	    out_str_nf((char_u *)"\033['z");
	mouse_ison = on;
    }
# endif

# ifdef FEAT_MOUSE_GPM
    else
    {
	if (on)
	{
	    if (gpm_open())
		mouse_ison = TRUE;
	}
	else
	{
	    gpm_close();
	    mouse_ison = FALSE;
	}
    }
# endif

# ifdef FEAT_SYSMOUSE
    else
    {
	if (on)
	{
	    if (sysmouse_open() == OK)
		mouse_ison = TRUE;
	}
	else
	{
	    sysmouse_close();
	    mouse_ison = FALSE;
	}
    }
# endif

# ifdef FEAT_MOUSE_JSB
    else
    {
	if (on)
	{
	    /* D - Enable Mouse up/down messages
	     * L - Enable Left Button Reporting
	     * M - Enable Middle Button Reporting
	     * R - Enable Right Button Reporting
	     * K - Enable SHIFT and CTRL key Reporting
	     * + - Enable Advanced messaging of mouse moves and up/down messages
	     * Q - Quiet No Ack
	     * # - Numeric value of mouse pointer required
	     *	  0 = Multiview 2000 cursor, used as standard
	     *	  1 = Windows Arrow
	     *	  2 = Windows I Beam
	     *	  3 = Windows Hour Glass
	     *	  4 = Windows Cross Hair
	     *	  5 = Windows UP Arrow
	     */
#  ifdef JSBTERM_MOUSE_NONADVANCED
	    /* Disables full feedback of pointer movements */
	    out_str_nf((char_u *)IF_EB("\033[0~ZwLMRK1Q\033\\",
					 ESC_STR "[0~ZwLMRK1Q" ESC_STR "\\"));
#  else
	    out_str_nf((char_u *)IF_EB("\033[0~ZwLMRK+1Q\033\\",
					ESC_STR "[0~ZwLMRK+1Q" ESC_STR "\\"));
#  endif
	    mouse_ison = TRUE;
	}
	else
	{
	    out_str_nf((char_u *)IF_EB("\033[0~ZwQ\033\\",
					      ESC_STR "[0~ZwQ" ESC_STR "\\"));
	    mouse_ison = FALSE;
	}
    }
# endif
# ifdef FEAT_MOUSE_PTERM
    else
    {
	/* 1 = button press, 6 = release, 7 = drag, 1h...9l = right button */
	if (on)
	    out_str_nf("\033[>1h\033[>6h\033[>7h\033[>1h\033[>9l");
	else
	    out_str_nf("\033[>1l\033[>6l\033[>7l\033[>1l\033[>9h");
	mouse_ison = on;
    }
# endif
}

#if defined(FEAT_BEVAL_TERM) || defined(PROTO)
/*
 * Called when 'balloonevalterm' changed.
 */
    void
mch_bevalterm_changed(void)
{
    mch_setmouse(mouse_ison);
}
#endif

/*
 * Set the mouse termcode, depending on the 'term' and 'ttymouse' options.
 */
    void
check_mouse_termcode(void)
{
# ifdef FEAT_MOUSE_XTERM
    if (use_xterm_mouse()
# ifdef FEAT_MOUSE_URXVT
	    && use_xterm_mouse() != 3
# endif
#  ifdef FEAT_GUI
	    && !gui.in_use
#  endif
	    )
    {
	set_mouse_termcode(KS_MOUSE, (char_u *)(term_is_8bit(T_NAME)
		    ? IF_EB("\233M", CSI_STR "M")
		    : IF_EB("\033[M", ESC_STR "[M")));
	if (*p_mouse != NUL)
	{
	    /* force mouse off and maybe on to send possibly new mouse
	     * activation sequence to the xterm, with(out) drag tracing. */
	    mch_setmouse(FALSE);
	    setmouse();
	}
    }
    else
	del_mouse_termcode(KS_MOUSE);
# endif

# ifdef FEAT_MOUSE_GPM
    if (!use_xterm_mouse()
#  ifdef FEAT_GUI
	    && !gui.in_use
#  endif
	    )
	set_mouse_termcode(KS_MOUSE, (char_u *)IF_EB("\033MG", ESC_STR "MG"));
# endif

# ifdef FEAT_SYSMOUSE
    if (!use_xterm_mouse()
#  ifdef FEAT_GUI
	    && !gui.in_use
#  endif
	    )
	set_mouse_termcode(KS_MOUSE, (char_u *)IF_EB("\033MS", ESC_STR "MS"));
# endif

# ifdef FEAT_MOUSE_JSB
    /* Conflicts with xterm mouse: "\033[" and "\033[M" ??? */
    if (!use_xterm_mouse()
#  ifdef FEAT_GUI
	    && !gui.in_use
#  endif
	    )
	set_mouse_termcode(KS_JSBTERM_MOUSE,
			       (char_u *)IF_EB("\033[0~zw", ESC_STR "[0~zw"));
    else
	del_mouse_termcode(KS_JSBTERM_MOUSE);
# endif

# ifdef FEAT_MOUSE_NET
    /* There is no conflict, but one may type "ESC }" from Insert mode.  Don't
     * define it in the GUI or when using an xterm. */
    if (!use_xterm_mouse()
#  ifdef FEAT_GUI
	    && !gui.in_use
#  endif
	    )
	set_mouse_termcode(KS_NETTERM_MOUSE,
				       (char_u *)IF_EB("\033}", ESC_STR "}"));
    else
	del_mouse_termcode(KS_NETTERM_MOUSE);
# endif

# ifdef FEAT_MOUSE_DEC
    /* Conflicts with xterm mouse: "\033[" and "\033[M" */
    if (!use_xterm_mouse()
#  ifdef FEAT_GUI
	    && !gui.in_use
#  endif
	    )
	set_mouse_termcode(KS_DEC_MOUSE, (char_u *)(term_is_8bit(T_NAME)
		     ? IF_EB("\233", CSI_STR) : IF_EB("\033[", ESC_STR "[")));
    else
	del_mouse_termcode(KS_DEC_MOUSE);
# endif
# ifdef FEAT_MOUSE_PTERM
    /* same conflict as the dec mouse */
    if (!use_xterm_mouse()
#  ifdef FEAT_GUI
	    && !gui.in_use
#  endif
	    )
	set_mouse_termcode(KS_PTERM_MOUSE,
				      (char_u *) IF_EB("\033[", ESC_STR "["));
    else
	del_mouse_termcode(KS_PTERM_MOUSE);
# endif
# ifdef FEAT_MOUSE_URXVT
    if (use_xterm_mouse() == 3
#  ifdef FEAT_GUI
	    && !gui.in_use
#  endif
	    )
    {
	set_mouse_termcode(KS_URXVT_MOUSE, (char_u *)(term_is_8bit(T_NAME)
		    ? IF_EB("\233*M", CSI_STR "*M")
		    : IF_EB("\033[*M", ESC_STR "[*M")));

	if (*p_mouse != NUL)
	{
	    mch_setmouse(FALSE);
	    setmouse();
	}
    }
    else
	del_mouse_termcode(KS_URXVT_MOUSE);
# endif
# ifdef FEAT_MOUSE_SGR
    if (use_xterm_mouse() == 4
#  ifdef FEAT_GUI
	    && !gui.in_use
#  endif
	    )
    {
	set_mouse_termcode(KS_SGR_MOUSE, (char_u *)(term_is_8bit(T_NAME)
		    ? IF_EB("\233<*M", CSI_STR "<*M")
		    : IF_EB("\033[<*M", ESC_STR "[<*M")));

	set_mouse_termcode(KS_SGR_MOUSE_RELEASE, (char_u *)(term_is_8bit(T_NAME)
		    ? IF_EB("\233<*m", CSI_STR "<*m")
		    : IF_EB("\033[<*m", ESC_STR "[<*m")));

	if (*p_mouse != NUL)
	{
	    mch_setmouse(FALSE);
	    setmouse();
	}
    }
    else
    {
	del_mouse_termcode(KS_SGR_MOUSE);
	del_mouse_termcode(KS_SGR_MOUSE_RELEASE);
    }
# endif
}
#endif

/*
 * set screen mode, always fails.
 */
    int
mch_screenmode(char_u *arg UNUSED)
{
    emsg(_(e_screenmode));
    return FAIL;
}

#ifndef VMS

/*
 * Try to get the current window size:
 * 1. with an ioctl(), most accurate method
 * 2. from the environment variables LINES and COLUMNS
 * 3. from the termcap
 * 4. keep using the old values
 * Return OK when size could be determined, FAIL otherwise.
 */
    int
mch_get_shellsize(void)
{
    long	rows = 0;
    long	columns = 0;
    char_u	*p;

    /*
     * 1. try using an ioctl. It is the most accurate method.
     *
     * Try using TIOCGWINSZ first, some systems that have it also define
     * TIOCGSIZE but don't have a struct ttysize.
     */
# ifdef TIOCGWINSZ
    {
	struct winsize	ws;
	int fd = 1;

	/* When stdout is not a tty, use stdin for the ioctl(). */
	if (!isatty(fd) && isatty(read_cmd_fd))
	    fd = read_cmd_fd;
	if (ioctl(fd, TIOCGWINSZ, &ws) == 0)
	{
	    columns = ws.ws_col;
	    rows = ws.ws_row;
	}
    }
# else /* TIOCGWINSZ */
#  ifdef TIOCGSIZE
    {
	struct ttysize	ts;
	int fd = 1;

	/* When stdout is not a tty, use stdin for the ioctl(). */
	if (!isatty(fd) && isatty(read_cmd_fd))
	    fd = read_cmd_fd;
	if (ioctl(fd, TIOCGSIZE, &ts) == 0)
	{
	    columns = ts.ts_cols;
	    rows = ts.ts_lines;
	}
    }
#  endif /* TIOCGSIZE */
# endif /* TIOCGWINSZ */

    /*
     * 2. get size from environment
     *    When being POSIX compliant ('|' flag in 'cpoptions') this overrules
     *    the ioctl() values!
     */
    if (columns == 0 || rows == 0 || vim_strchr(p_cpo, CPO_TSIZE) != NULL)
    {
	if ((p = (char_u *)getenv("LINES")))
	    rows = atoi((char *)p);
	if ((p = (char_u *)getenv("COLUMNS")))
	    columns = atoi((char *)p);
    }

#ifdef HAVE_TGETENT
    /*
     * 3. try reading "co" and "li" entries from termcap
     */
    if (columns == 0 || rows == 0)
	getlinecol(&columns, &rows);
#endif

    /*
     * 4. If everything fails, use the old values
     */
    if (columns <= 0 || rows <= 0)
	return FAIL;

    Rows = rows;
    Columns = columns;
    limit_screen_size();
    return OK;
}

#if defined(FEAT_TERMINAL) || defined(PROTO)
/*
 * Report the windows size "rows" and "cols" to tty "fd".
 */
    int
mch_report_winsize(int fd, int rows, int cols)
{
# ifdef TIOCSWINSZ
    struct winsize	ws;

    ws.ws_col = cols;
    ws.ws_row = rows;
    ws.ws_xpixel = cols * 5;
    ws.ws_ypixel = rows * 10;
    if (ioctl(fd, TIOCSWINSZ, &ws) == 0)
    {
	ch_log(NULL, "ioctl(TIOCSWINSZ) success");
	return OK;
    }
    ch_log(NULL, "ioctl(TIOCSWINSZ) failed");
# else
#  ifdef TIOCSSIZE
    struct ttysize	ts;

    ts.ts_cols = cols;
    ts.ts_lines = rows;
    if (ioctl(fd, TIOCSSIZE, &ws) == 0)
    {
	ch_log(NULL, "ioctl(TIOCSSIZE) success");
	return OK;
    }
    ch_log(NULL, "ioctl(TIOCSSIZE) failed");
#  endif
# endif
    return FAIL;
}
#endif

/*
 * Try to set the window size to Rows and Columns.
 */
    void
mch_set_shellsize(void)
{
    if (*T_CWS)
    {
	/*
	 * NOTE: if you get an error here that term_set_winsize() is
	 * undefined, check the output of configure.  It could probably not
	 * find a ncurses, termcap or termlib library.
	 */
	term_set_winsize((int)Rows, (int)Columns);
	out_flush();
	screen_start();			/* don't know where cursor is now */
    }
}

#endif /* VMS */

/*
 * Rows and/or Columns has changed.
 */
    void
mch_new_shellsize(void)
{
    /* Nothing to do. */
}

/*
 * Wait for process "child" to end.
 * Return "child" if it exited properly, <= 0 on error.
 */
    static pid_t
wait4pid(pid_t child, waitstatus *status)
{
    pid_t wait_pid = 0;
    long delay_msec = 1;

    while (wait_pid != child)
    {
	/* When compiled with Python threads are probably used, in which case
	 * wait() sometimes hangs for no obvious reason.  Use waitpid()
	 * instead and loop (like the GUI). Also needed for other interfaces,
	 * they might call system(). */
# ifdef __NeXT__
	wait_pid = wait4(child, status, WNOHANG, (struct rusage *)0);
# else
	wait_pid = waitpid(child, status, WNOHANG);
# endif
	if (wait_pid == 0)
	{
	    /* Wait for 1 to 10 msec before trying again. */
	    mch_delay(delay_msec, TRUE);
	    if (++delay_msec > 10)
		delay_msec = 10;
	    continue;
	}
	if (wait_pid <= 0
# ifdef ECHILD
		&& errno == ECHILD
# endif
	   )
	    break;
    }
    return wait_pid;
}

#if !defined(USE_SYSTEM) || defined(FEAT_JOB_CHANNEL)
/*
 * Set the environment for a child process.
 */
    static void
set_child_environment(
	long	rows,
	long	columns,
	char	*term,
	int	is_terminal UNUSED)
{
# ifdef HAVE_SETENV
    char	envbuf[50];
# else
    static char	envbuf_Term[30];
    static char	envbuf_Rows[20];
    static char	envbuf_Lines[20];
    static char	envbuf_Columns[20];
    static char	envbuf_Colors[20];
#  ifdef FEAT_TERMINAL
    static char	envbuf_Version[20];
#  endif
#  ifdef FEAT_CLIENTSERVER
    static char	envbuf_Servername[60];
#  endif
# endif
    long	colors =
#  ifdef FEAT_GUI
	    gui.in_use ? 256*256*256 :
#  endif
	    t_colors;

# ifdef HAVE_SETENV
    setenv("TERM", term, 1);
    sprintf((char *)envbuf, "%ld", rows);
    setenv("ROWS", (char *)envbuf, 1);
    sprintf((char *)envbuf, "%ld", rows);
    setenv("LINES", (char *)envbuf, 1);
    sprintf((char *)envbuf, "%ld", columns);
    setenv("COLUMNS", (char *)envbuf, 1);
    sprintf((char *)envbuf, "%ld", colors);
    setenv("COLORS", (char *)envbuf, 1);
#  ifdef FEAT_TERMINAL
    if (is_terminal)
    {
	sprintf((char *)envbuf, "%ld",  (long)get_vim_var_nr(VV_VERSION));
	setenv("VIM_TERMINAL", (char *)envbuf, 1);
    }
#  endif
#  ifdef FEAT_CLIENTSERVER
    setenv("VIM_SERVERNAME", serverName == NULL ? "" : (char *)serverName, 1);
#  endif
# else
    /*
     * Putenv does not copy the string, it has to remain valid.
     * Use a static array to avoid losing allocated memory.
     * This won't work well when running multiple children...
     */
    vim_snprintf(envbuf_Term, sizeof(envbuf_Term), "TERM=%s", term);
    putenv(envbuf_Term);
    vim_snprintf(envbuf_Rows, sizeof(envbuf_Rows), "ROWS=%ld", rows);
    putenv(envbuf_Rows);
    vim_snprintf(envbuf_Lines, sizeof(envbuf_Lines), "LINES=%ld", rows);
    putenv(envbuf_Lines);
    vim_snprintf(envbuf_Columns, sizeof(envbuf_Columns),
						       "COLUMNS=%ld", columns);
    putenv(envbuf_Columns);
    vim_snprintf(envbuf_Colors, sizeof(envbuf_Colors), "COLORS=%ld", colors);
    putenv(envbuf_Colors);
#  ifdef FEAT_TERMINAL
    if (is_terminal)
    {
	vim_snprintf(envbuf_Version, sizeof(envbuf_Version),
			 "VIM_TERMINAL=%ld", (long)get_vim_var_nr(VV_VERSION));
	putenv(envbuf_Version);
    }
#  endif
#  ifdef FEAT_CLIENTSERVER
    vim_snprintf(envbuf_Servername, sizeof(envbuf_Servername),
	    "VIM_SERVERNAME=%s", serverName == NULL ? "" : (char *)serverName);
    putenv(envbuf_Servername);
#  endif
# endif
}

    static void
set_default_child_environment(int is_terminal)
{
    set_child_environment(Rows, Columns, "dumb", is_terminal);
}
#endif

#if defined(FEAT_GUI) || defined(FEAT_JOB_CHANNEL)
/*
 * Open a PTY, with FD for the master and slave side.
 * When failing "pty_master_fd" and "pty_slave_fd" are -1.
 * When successful both file descriptors are stored.
 */
    static void
open_pty(int *pty_master_fd, int *pty_slave_fd, char_u **namep)
{
    char	*tty_name;

    *pty_master_fd = OpenPTY(&tty_name);	    /* open pty */
    if (*pty_master_fd >= 0)
    {
	/* Leaving out O_NOCTTY may lead to waitpid() always returning
	 * 0 on Mac OS X 10.7 thereby causing freezes. Let's assume
	 * adding O_NOCTTY always works when defined. */
#ifdef O_NOCTTY
	*pty_slave_fd = open(tty_name, O_RDWR | O_NOCTTY | O_EXTRA, 0);
#else
	*pty_slave_fd = open(tty_name, O_RDWR | O_EXTRA, 0);
#endif
	if (*pty_slave_fd < 0)
	{
	    close(*pty_master_fd);
	    *pty_master_fd = -1;
	}
	else if (namep != NULL)
	    *namep = vim_strsave((char_u *)tty_name);
    }
}
#endif

/*
 * Send SIGINT to a child process if "c" is an interrupt character.
 */
    void
may_send_sigint(int c UNUSED, pid_t pid UNUSED, pid_t wpid UNUSED)
{
# ifdef SIGINT
    if (c == Ctrl_C || c == intr_char)
    {
#  ifdef HAVE_SETSID
	kill(-pid, SIGINT);
#  else
	kill(0, SIGINT);
#  endif
	if (wpid > 0)
	    kill(wpid, SIGINT);
    }
# endif
}

#if !defined(USE_SYSTEM) || (defined(FEAT_GUI) && defined(FEAT_TERMINAL))

    static int
build_argv(
	char_u *cmd,
	char ***argvp,
	char_u **sh_tofree,
	char_u **shcf_tofree)
{
    char	**argv = NULL;
    int		argc;

    *sh_tofree = vim_strsave(p_sh);
    if (*sh_tofree == NULL)		/* out of memory */
	return FAIL;

    if (mch_parse_cmd(*sh_tofree, TRUE, &argv, &argc) == FAIL)
	return FAIL;
    *argvp = argv;

    if (cmd != NULL)
    {
	char_u	*s;
	char_u	*p;

	if (extra_shell_arg != NULL)
	    argv[argc++] = (char *)extra_shell_arg;

	/* Break 'shellcmdflag' into white separated parts.  This doesn't
	 * handle quoted strings, they are very unlikely to appear. */
	*shcf_tofree = alloc((unsigned)STRLEN(p_shcf) + 1);
	if (*shcf_tofree == NULL)    /* out of memory */
	    return FAIL;
	s = *shcf_tofree;
	p = p_shcf;
	while (*p != NUL)
	{
	    argv[argc++] = (char *)s;
	    while (*p && *p != ' ' && *p != TAB)
		*s++ = *p++;
	    *s++ = NUL;
	    p = skipwhite(p);
	}

	argv[argc++] = (char *)cmd;
    }
    argv[argc] = NULL;
    return OK;
}
#endif

#if defined(FEAT_GUI) && defined(FEAT_TERMINAL)
/*
 * Use a terminal window to run a shell command in.
 */
    static int
mch_call_shell_terminal(
    char_u	*cmd,
    int		options UNUSED)	/* SHELL_*, see vim.h */
{
    jobopt_T	opt;
    char	**argv = NULL;
    char_u	*tofree1 = NULL;
    char_u	*tofree2 = NULL;
    int		retval = -1;
    buf_T	*buf;
    job_T	*job;
    aco_save_T	aco;
    oparg_T	oa;		/* operator arguments */

    if (build_argv(cmd, &argv, &tofree1, &tofree2) == FAIL)
	goto theend;

    init_job_options(&opt);
    ch_log(NULL, "starting terminal for system command '%s'", cmd);
    buf = term_start(NULL, argv, &opt, TERM_START_SYSTEM);
    if (buf == NULL)
	goto theend;

    job = term_getjob(buf->b_term);
    ++job->jv_refcount;

    /* Find a window to make "buf" curbuf. */
    aucmd_prepbuf(&aco, buf);

    clear_oparg(&oa);
    while (term_use_loop())
    {
	if (oa.op_type == OP_NOP && oa.regname == NUL && !VIsual_active)
	{
	    /* If terminal_loop() returns OK we got a key that is handled
	     * in Normal model. We don't do redrawing anyway. */
	    if (terminal_loop(TRUE) == OK)
		normal_cmd(&oa, TRUE);
	}
	else
	    normal_cmd(&oa, TRUE);
    }
    retval = job->jv_exitval;
    ch_log(NULL, "system command finished");

    job_unref(job);

    /* restore curwin/curbuf and a few other things */
    aucmd_restbuf(&aco);

    wait_return(TRUE);
    do_buffer(DOBUF_WIPE, DOBUF_FIRST, FORWARD, buf->b_fnum, TRUE);

theend:
    vim_free(argv);
    vim_free(tofree1);
    vim_free(tofree2);
    return retval;
}
#endif

#ifdef USE_SYSTEM
/*
 * Use system() to start the shell: simple but slow.
 */
    static int
mch_call_shell_system(
    char_u	*cmd,
    int		options)	/* SHELL_*, see vim.h */
{
#ifdef VMS
    char	*ifn = NULL;
    char	*ofn = NULL;
#endif
    int		tmode = cur_tmode;
    char_u	*newcmd;	/* only needed for unix */
    int		x;

    out_flush();

    if (options & SHELL_COOKED)
	settmode(TMODE_COOK);	    /* set to normal mode */

# if defined(FEAT_CLIPBOARD) && defined(FEAT_X11)
    save_clipboard();
    loose_clipboard();
# endif

    if (cmd == NULL)
	x = system((char *)p_sh);
    else
    {
# ifdef VMS
	if (ofn = strchr((char *)cmd, '>'))
	    *ofn++ = '\0';
	if (ifn = strchr((char *)cmd, '<'))
	{
	    char *p;

	    *ifn++ = '\0';
	    p = strchr(ifn,' '); /* chop off any trailing spaces */
	    if (p)
		*p = '\0';
	}
	if (ofn)
	    x = vms_sys((char *)cmd, ofn, ifn);
	else
	    x = system((char *)cmd);
# else
	newcmd = lalloc(STRLEN(p_sh)
		+ (extra_shell_arg == NULL ? 0 : STRLEN(extra_shell_arg))
		+ STRLEN(p_shcf) + STRLEN(cmd) + 4, TRUE);
	if (newcmd == NULL)
	    x = 0;
	else
	{
	    sprintf((char *)newcmd, "%s %s %s %s", p_sh,
		    extra_shell_arg == NULL ? "" : (char *)extra_shell_arg,
		    (char *)p_shcf,
		    (char *)cmd);
	    x = system((char *)newcmd);
	    vim_free(newcmd);
	}
# endif
    }
# ifdef VMS
    x = vms_sys_status(x);
# endif
    if (emsg_silent)
	;
    else if (x == 127)
	msg_puts(_("\nCannot execute shell sh\n"));
    else if (x && !(options & SHELL_SILENT))
    {
	msg_puts(_("\nshell returned "));
	msg_outnum((long)x);
	msg_putchar('\n');
    }

    if (tmode == TMODE_RAW)
	settmode(TMODE_RAW);	/* set to raw mode */
# ifdef FEAT_TITLE
    resettitle();
# endif
# if defined(FEAT_CLIPBOARD) && defined(FEAT_X11)
    restore_clipboard();
# endif
    return x;
}

#else /* USE_SYSTEM */

# define EXEC_FAILED 122    /* Exit code when shell didn't execute.  Don't use
			       127, some shells use that already */
# define OPEN_NULL_FAILED 123 /* Exit code if /dev/null can't be opened */

/*
 * Don't use system(), use fork()/exec().
 */
    static int
mch_call_shell_fork(
    char_u	*cmd,
    int		options)	/* SHELL_*, see vim.h */
{
    int		tmode = cur_tmode;
    pid_t	pid;
    pid_t	wpid = 0;
    pid_t	wait_pid = 0;
# ifdef HAVE_UNION_WAIT
    union wait	status;
# else
    int		status = -1;
# endif
    int		retval = -1;
    char	**argv = NULL;
    char_u	*tofree1 = NULL;
    char_u	*tofree2 = NULL;
    int		i;
    int		pty_master_fd = -1;	    /* for pty's */
# ifdef FEAT_GUI
    int		pty_slave_fd = -1;
# endif
    int		fd_toshell[2];		/* for pipes */
    int		fd_fromshell[2];
    int		pipe_error = FALSE;
    int		did_settmode = FALSE;	/* settmode(TMODE_RAW) called */

    out_flush();
    if (options & SHELL_COOKED)
	settmode(TMODE_COOK);		/* set to normal mode */

    if (build_argv(cmd, &argv, &tofree1, &tofree2) == FAIL)
	goto error;

    /*
     * For the GUI, when writing the output into the buffer and when reading
     * input from the buffer: Try using a pseudo-tty to get the stdin/stdout
     * of the executed command into the Vim window.  Or use a pipe.
     */
    if ((options & (SHELL_READ|SHELL_WRITE))
# ifdef FEAT_GUI
	    || (gui.in_use && show_shell_mess)
# endif
		    )
    {
# ifdef FEAT_GUI
	/*
	 * Try to open a master pty.
	 * If this works, open the slave pty.
	 * If the slave can't be opened, close the master pty.
	 */
	if (p_guipty && !(options & (SHELL_READ|SHELL_WRITE)))
	    open_pty(&pty_master_fd, &pty_slave_fd, NULL);
	/*
	 * If not opening a pty or it didn't work, try using pipes.
	 */
	if (pty_master_fd < 0)
# endif
	{
	    pipe_error = (pipe(fd_toshell) < 0);
	    if (!pipe_error)			    /* pipe create OK */
	    {
		pipe_error = (pipe(fd_fromshell) < 0);
		if (pipe_error)			    /* pipe create failed */
		{
		    close(fd_toshell[0]);
		    close(fd_toshell[1]);
		}
	    }
	    if (pipe_error)
	    {
		msg_puts(_("\nCannot create pipes\n"));
		out_flush();
	    }
	}
    }

    if (!pipe_error)			/* pty or pipe opened or not used */
    {
	SIGSET_DECL(curset)

# ifdef __BEOS__
	beos_cleanup_read_thread();
# endif

	BLOCK_SIGNALS(&curset);
	pid = fork();	/* maybe we should use vfork() */
	if (pid == -1)
	{
	    UNBLOCK_SIGNALS(&curset);

	    msg_puts(_("\nCannot fork\n"));
	    if ((options & (SHELL_READ|SHELL_WRITE))
# ifdef FEAT_GUI
		|| (gui.in_use && show_shell_mess)
# endif
		    )
	    {
# ifdef FEAT_GUI
		if (pty_master_fd >= 0)		/* close the pseudo tty */
		{
		    close(pty_master_fd);
		    close(pty_slave_fd);
		}
		else				/* close the pipes */
# endif
		{
		    close(fd_toshell[0]);
		    close(fd_toshell[1]);
		    close(fd_fromshell[0]);
		    close(fd_fromshell[1]);
		}
	    }
	}
	else if (pid == 0)	/* child */
	{
	    reset_signals();		/* handle signals normally */
	    UNBLOCK_SIGNALS(&curset);

# ifdef FEAT_JOB_CHANNEL
	    if (ch_log_active())
		/* close the log file in the child */
		ch_logfile((char_u *)"", (char_u *)"");
# endif

	    if (!show_shell_mess || (options & SHELL_EXPAND))
	    {
		int fd;

		/*
		 * Don't want to show any message from the shell.  Can't just
		 * close stdout and stderr though, because some systems will
		 * break if you try to write to them after that, so we must
		 * use dup() to replace them with something else -- webb
		 * Connect stdin to /dev/null too, so ":n `cat`" doesn't hang,
		 * waiting for input.
		 */
		fd = open("/dev/null", O_RDWR | O_EXTRA, 0);
		fclose(stdin);
		fclose(stdout);
		fclose(stderr);

		/*
		 * If any of these open()'s and dup()'s fail, we just continue
		 * anyway.  It's not fatal, and on most systems it will make
		 * no difference at all.  On a few it will cause the execvp()
		 * to exit with a non-zero status even when the completion
		 * could be done, which is nothing too serious.  If the open()
		 * or dup() failed we'd just do the same thing ourselves
		 * anyway -- webb
		 */
		if (fd >= 0)
		{
		    vim_ignored = dup(fd); /* To replace stdin  (fd 0) */
		    vim_ignored = dup(fd); /* To replace stdout (fd 1) */
		    vim_ignored = dup(fd); /* To replace stderr (fd 2) */

		    /* Don't need this now that we've duplicated it */
		    close(fd);
		}
	    }
	    else if ((options & (SHELL_READ|SHELL_WRITE))
# ifdef FEAT_GUI
		    || gui.in_use
# endif
		    )
	    {

# ifdef HAVE_SETSID
		/* Create our own process group, so that the child and all its
		 * children can be kill()ed.  Don't do this when using pipes,
		 * because stdin is not a tty, we would lose /dev/tty. */
		if (p_stmp)
		{
		    (void)setsid();
#  if defined(SIGHUP)
		    /* When doing "!xterm&" and 'shell' is bash: the shell
		     * will exit and send SIGHUP to all processes in its
		     * group, killing the just started process.  Ignore SIGHUP
		     * to avoid that. (suggested by Simon Schubert)
		     */
		    signal(SIGHUP, SIG_IGN);
#  endif
		}
# endif
# ifdef FEAT_GUI
		if (pty_slave_fd >= 0)
		{
		    /* push stream discipline modules */
		    if (options & SHELL_COOKED)
			SetupSlavePTY(pty_slave_fd);
#  ifdef TIOCSCTTY
		    /* Try to become controlling tty (probably doesn't work,
		     * unless run by root) */
		    ioctl(pty_slave_fd, TIOCSCTTY, (char *)NULL);
#  endif
		}
# endif
		set_default_child_environment(FALSE);

		/*
		 * stderr is only redirected when using the GUI, so that a
		 * program like gpg can still access the terminal to get a
		 * passphrase using stderr.
		 */
# ifdef FEAT_GUI
		if (pty_master_fd >= 0)
		{
		    close(pty_master_fd);   /* close master side of pty */

		    /* set up stdin/stdout/stderr for the child */
		    close(0);
		    vim_ignored = dup(pty_slave_fd);
		    close(1);
		    vim_ignored = dup(pty_slave_fd);
		    if (gui.in_use)
		    {
			close(2);
			vim_ignored = dup(pty_slave_fd);
		    }

		    close(pty_slave_fd);    /* has been dupped, close it now */
		}
		else
# endif
		{
		    /* set up stdin for the child */
		    close(fd_toshell[1]);
		    close(0);
		    vim_ignored = dup(fd_toshell[0]);
		    close(fd_toshell[0]);

		    /* set up stdout for the child */
		    close(fd_fromshell[0]);
		    close(1);
		    vim_ignored = dup(fd_fromshell[1]);
		    close(fd_fromshell[1]);

# ifdef FEAT_GUI
		    if (gui.in_use)
		    {
			/* set up stderr for the child */
			close(2);
			vim_ignored = dup(1);
		    }
# endif
		}
	    }

	    /*
	     * There is no type cast for the argv, because the type may be
	     * different on different machines. This may cause a warning
	     * message with strict compilers, don't worry about it.
	     * Call _exit() instead of exit() to avoid closing the connection
	     * to the X server (esp. with GTK, which uses atexit()).
	     */
	    execvp(argv[0], argv);
	    _exit(EXEC_FAILED);	    /* exec failed, return failure code */
	}
	else			/* parent */
	{
	    /*
	     * While child is running, ignore terminating signals.
	     * Do catch CTRL-C, so that "got_int" is set.
	     */
	    catch_signals(SIG_IGN, SIG_ERR);
	    catch_int_signal();
	    UNBLOCK_SIGNALS(&curset);
# ifdef FEAT_JOB_CHANNEL
	    ++dont_check_job_ended;
# endif
	    /*
	     * For the GUI we redirect stdin, stdout and stderr to our window.
	     * This is also used to pipe stdin/stdout to/from the external
	     * command.
	     */
	    if ((options & (SHELL_READ|SHELL_WRITE))
# ifdef FEAT_GUI
		    || (gui.in_use && show_shell_mess)
# endif
	       )
	    {
# define BUFLEN 100		/* length for buffer, pseudo tty limit is 128 */
		char_u	    buffer[BUFLEN + 1];
# ifdef FEAT_MBYTE
		int	    buffer_off = 0;	/* valid bytes in buffer[] */
# endif
		char_u	    ta_buf[BUFLEN + 1];	/* TypeAHead */
		int	    ta_len = 0;		/* valid bytes in ta_buf[] */
		int	    len;
		int	    p_more_save;
		int	    old_State;
		int	    c;
		int	    toshell_fd;
		int	    fromshell_fd;
		garray_T    ga;
		int	    noread_cnt;
# ifdef ELAPSED_FUNC
		elapsed_T   start_tv;
# endif

# ifdef FEAT_GUI
		if (pty_master_fd >= 0)
		{
		    fromshell_fd = pty_master_fd;
		    toshell_fd = dup(pty_master_fd);
		}
		else
# endif
		{
		    close(fd_toshell[0]);
		    close(fd_fromshell[1]);
		    toshell_fd = fd_toshell[1];
		    fromshell_fd = fd_fromshell[0];
		}

		/*
		 * Write to the child if there are typed characters.
		 * Read from the child if there are characters available.
		 *   Repeat the reading a few times if more characters are
		 *   available. Need to check for typed keys now and then, but
		 *   not too often (delays when no chars are available).
		 * This loop is quit if no characters can be read from the pty
		 * (WaitForChar detected special condition), or there are no
		 * characters available and the child has exited.
		 * Only check if the child has exited when there is no more
		 * output. The child may exit before all the output has
		 * been printed.
		 *
		 * Currently this busy loops!
		 * This can probably dead-lock when the write blocks!
		 */
		p_more_save = p_more;
		p_more = FALSE;
		old_State = State;
		State = EXTERNCMD;	/* don't redraw at window resize */

		if ((options & SHELL_WRITE) && toshell_fd >= 0)
		{
		    /* Fork a process that will write the lines to the
		     * external program. */
		    if ((wpid = fork()) == -1)
		    {
			msg_puts(_("\nCannot fork\n"));
		    }
		    else if (wpid == 0) /* child */
		    {
			linenr_T    lnum = curbuf->b_op_start.lnum;
			int	    written = 0;
			char_u	    *lp = ml_get(lnum);
			size_t	    l;

			close(fromshell_fd);
			for (;;)
			{
			    l = STRLEN(lp + written);
			    if (l == 0)
				len = 0;
			    else if (lp[written] == NL)
				/* NL -> NUL translation */
				len = write(toshell_fd, "", (size_t)1);
			    else
			    {
				char_u	*s = vim_strchr(lp + written, NL);

				len = write(toshell_fd, (char *)lp + written,
					   s == NULL ? l
					      : (size_t)(s - (lp + written)));
			    }
			    if (len == (int)l)
			    {
				/* Finished a line, add a NL, unless this line
				 * should not have one. */
				if (lnum != curbuf->b_op_end.lnum
					|| (!curbuf->b_p_bin
					    && curbuf->b_p_fixeol)
					|| (lnum != curbuf->b_no_eol_lnum
					    && (lnum !=
						    curbuf->b_ml.ml_line_count
						    || curbuf->b_p_eol)))
				    vim_ignored = write(toshell_fd, "\n",
								   (size_t)1);
				++lnum;
				if (lnum > curbuf->b_op_end.lnum)
				{
				    /* finished all the lines, close pipe */
				    close(toshell_fd);
				    toshell_fd = -1;
				    break;
				}
				lp = ml_get(lnum);
				written = 0;
			    }
			    else if (len > 0)
				written += len;
			}
			_exit(0);
		    }
		    else /* parent */
		    {
			close(toshell_fd);
			toshell_fd = -1;
		    }
		}

		if (options & SHELL_READ)
		    ga_init2(&ga, 1, BUFLEN);

		noread_cnt = 0;
# ifdef ELAPSED_FUNC
		ELAPSED_INIT(start_tv);
# endif
		for (;;)
		{
		    /*
		     * Check if keys have been typed, write them to the child
		     * if there are any.
		     * Don't do this if we are expanding wild cards (would eat
		     * typeahead).
		     * Don't do this when filtering and terminal is in cooked
		     * mode, the shell command will handle the I/O.  Avoids
		     * that a typed password is echoed for ssh or gpg command.
		     * Don't get characters when the child has already
		     * finished (wait_pid == 0).
		     * Don't read characters unless we didn't get output for a
		     * while (noread_cnt > 4), avoids that ":r !ls" eats
		     * typeahead.
		     */
		    len = 0;
		    if (!(options & SHELL_EXPAND)
			    && ((options &
					 (SHELL_READ|SHELL_WRITE|SHELL_COOKED))
				      != (SHELL_READ|SHELL_WRITE|SHELL_COOKED)
# ifdef FEAT_GUI
						    || gui.in_use
# endif
						    )
			    && wait_pid == 0
			    && (ta_len > 0 || noread_cnt > 4))
		    {
		      if (ta_len == 0)
		      {
			  /* Get extra characters when we don't have any.
			   * Reset the counter and timer. */
			  noread_cnt = 0;
# ifdef ELAPSED_FUNC
			  ELAPSED_INIT(start_tv);
# endif
			  len = ui_inchar(ta_buf, BUFLEN, 10L, 0);
		      }
		      if (ta_len > 0 || len > 0)
		      {
			/*
			 * For pipes:
			 * Check for CTRL-C: send interrupt signal to child.
			 * Check for CTRL-D: EOF, close pipe to child.
			 */
			if (len == 1 && (pty_master_fd < 0 || cmd != NULL))
			{
			    /*
			     * Send SIGINT to the child's group or all
			     * processes in our group.
			     */
			    may_send_sigint(ta_buf[ta_len], pid, wpid);

			    if (pty_master_fd < 0 && toshell_fd >= 0
					       && ta_buf[ta_len] == Ctrl_D)
			    {
				close(toshell_fd);
				toshell_fd = -1;
			    }
			}

			/* replace K_BS by <BS> and K_DEL by <DEL> */
			for (i = ta_len; i < ta_len + len; ++i)
			{
			    if (ta_buf[i] == CSI && len - i > 2)
			    {
				c = TERMCAP2KEY(ta_buf[i + 1], ta_buf[i + 2]);
				if (c == K_DEL || c == K_KDEL || c == K_BS)
				{
				    mch_memmove(ta_buf + i + 1, ta_buf + i + 3,
						       (size_t)(len - i - 2));
				    if (c == K_DEL || c == K_KDEL)
					ta_buf[i] = DEL;
				    else
					ta_buf[i] = Ctrl_H;
				    len -= 2;
				}
			    }
			    else if (ta_buf[i] == '\r')
				ta_buf[i] = '\n';
# ifdef FEAT_MBYTE
			    if (has_mbyte)
				i += (*mb_ptr2len_len)(ta_buf + i,
							ta_len + len - i) - 1;
# endif
			}

			/*
			 * For pipes: echo the typed characters.
			 * For a pty this does not seem to work.
			 */
			if (pty_master_fd < 0)
			{
			    for (i = ta_len; i < ta_len + len; ++i)
			    {
				if (ta_buf[i] == '\n' || ta_buf[i] == '\b')
				    msg_putchar(ta_buf[i]);
# ifdef FEAT_MBYTE
				else if (has_mbyte)
				{
				    int l = (*mb_ptr2len)(ta_buf + i);

				    msg_outtrans_len(ta_buf + i, l);
				    i += l - 1;
				}
# endif
				else
				    msg_outtrans_len(ta_buf + i, 1);
			    }
			    windgoto(msg_row, msg_col);
			    out_flush();
			}

			ta_len += len;

			/*
			 * Write the characters to the child, unless EOF has
			 * been typed for pipes.  Write one character at a
			 * time, to avoid losing too much typeahead.
			 * When writing buffer lines, drop the typed
			 * characters (only check for CTRL-C).
			 */
			if (options & SHELL_WRITE)
			    ta_len = 0;
			else if (toshell_fd >= 0)
			{
			    len = write(toshell_fd, (char *)ta_buf, (size_t)1);
			    if (len > 0)
			    {
				ta_len -= len;
				mch_memmove(ta_buf, ta_buf + len, ta_len);
			    }
			}
		      }
		    }

		    if (got_int)
		    {
			/* CTRL-C sends a signal to the child, we ignore it
			 * ourselves */
#  ifdef HAVE_SETSID
			kill(-pid, SIGINT);
#  else
			kill(0, SIGINT);
#  endif
			if (wpid > 0)
			    kill(wpid, SIGINT);
			got_int = FALSE;
		    }

		    /*
		     * Check if the child has any characters to be printed.
		     * Read them and write them to our window.	Repeat this as
		     * long as there is something to do, avoid the 10ms wait
		     * for mch_inchar(), or sending typeahead characters to
		     * the external process.
		     * TODO: This should handle escape sequences, compatible
		     * to some terminal (vt52?).
		     */
		    ++noread_cnt;
		    while (RealWaitForChar(fromshell_fd, 10L, NULL, NULL))
		    {
			len = read_eintr(fromshell_fd, buffer
# ifdef FEAT_MBYTE
				+ buffer_off, (size_t)(BUFLEN - buffer_off)
# else
				, (size_t)BUFLEN
# endif
				);
			if (len <= 0)		    /* end of file or error */
			    goto finished;

			noread_cnt = 0;
			if (options & SHELL_READ)
			{
			    /* Do NUL -> NL translation, append NL separated
			     * lines to the current buffer. */
			    for (i = 0; i < len; ++i)
			    {
				if (buffer[i] == NL)
				    append_ga_line(&ga);
				else if (buffer[i] == NUL)
				    ga_append(&ga, NL);
				else
				    ga_append(&ga, buffer[i]);
			    }
			}
# ifdef FEAT_MBYTE
			else if (has_mbyte)
			{
			    int		l;
			    char_u	*p;

			    len += buffer_off;
			    buffer[len] = NUL;

			    /* Check if the last character in buffer[] is
			     * incomplete, keep these bytes for the next
			     * round. */
			    for (p = buffer; p < buffer + len; p += l)
			    {
				l = MB_CPTR2LEN(p);
				if (l == 0)
				    l = 1;  /* NUL byte? */
				else if (MB_BYTE2LEN(*p) != l)
				    break;
			    }
			    if (p == buffer)	/* no complete character */
			    {
				/* avoid getting stuck at an illegal byte */
				if (len >= 12)
				    ++p;
				else
				{
				    buffer_off = len;
				    continue;
				}
			    }
			    c = *p;
			    *p = NUL;
			    msg_puts((char *)buffer);
			    if (p < buffer + len)
			    {
				*p = c;
				buffer_off = (buffer + len) - p;
				mch_memmove(buffer, p, buffer_off);
				continue;
			    }
			    buffer_off = 0;
			}
# endif /* FEAT_MBYTE */
			else
			{
			    buffer[len] = NUL;
			    msg_puts((char *)buffer);
			}

			windgoto(msg_row, msg_col);
			cursor_on();
			out_flush();
			if (got_int)
			    break;

# ifdef ELAPSED_FUNC
			if (wait_pid == 0)
			{
			    long	msec = ELAPSED_FUNC(start_tv);

			    /* Avoid that we keep looping here without
			     * checking for a CTRL-C for a long time.  Don't
			     * break out too often to avoid losing typeahead. */
			    if (msec > 2000)
			    {
				noread_cnt = 5;
				break;
			    }
			}
# endif
		    }

		    /* If we already detected the child has finished, continue
		     * reading output for a short while.  Some text may be
		     * buffered. */
		    if (wait_pid == pid)
		    {
			if (noread_cnt < 5)
			    continue;
			break;
		    }

		    /*
		     * Check if the child still exists, before checking for
		     * typed characters (otherwise we would lose typeahead).
		     */
# ifdef __NeXT__
		    wait_pid = wait4(pid, &status, WNOHANG, (struct rusage *)0);
# else
		    wait_pid = waitpid(pid, &status, WNOHANG);
# endif
		    if ((wait_pid == (pid_t)-1 && errno == ECHILD)
			    || (wait_pid == pid && WIFEXITED(status)))
		    {
			/* Don't break the loop yet, try reading more
			 * characters from "fromshell_fd" first.  When using
			 * pipes there might still be something to read and
			 * then we'll break the loop at the "break" above. */
			wait_pid = pid;
		    }
		    else
			wait_pid = 0;

# if defined(FEAT_XCLIPBOARD) && defined(FEAT_X11)
		    /* Handle any X events, e.g. serving the clipboard. */
		    clip_update();
# endif
		}
finished:
		p_more = p_more_save;
		if (options & SHELL_READ)
		{
		    if (ga.ga_len > 0)
		    {
			append_ga_line(&ga);
			/* remember that the NL was missing */
			curbuf->b_no_eol_lnum = curwin->w_cursor.lnum;
		    }
		    else
			curbuf->b_no_eol_lnum = 0;
		    ga_clear(&ga);
		}

		/*
		 * Give all typeahead that wasn't used back to ui_inchar().
		 */
		if (ta_len)
		    ui_inchar_undo(ta_buf, ta_len);
		State = old_State;
		if (toshell_fd >= 0)
		    close(toshell_fd);
		close(fromshell_fd);
	    }
# if defined(FEAT_XCLIPBOARD) && defined(FEAT_X11)
	    else
	    {
		long delay_msec = 1;

		/*
		 * Similar to the loop above, but only handle X events, no
		 * I/O.
		 */
		for (;;)
		{
		    if (got_int)
		    {
			/* CTRL-C sends a signal to the child, we ignore it
			 * ourselves */
#  ifdef HAVE_SETSID
			kill(-pid, SIGINT);
#  else
			kill(0, SIGINT);
#  endif
			got_int = FALSE;
		    }
# ifdef __NeXT__
		    wait_pid = wait4(pid, &status, WNOHANG, (struct rusage *)0);
# else
		    wait_pid = waitpid(pid, &status, WNOHANG);
# endif
		    if ((wait_pid == (pid_t)-1 && errno == ECHILD)
			    || (wait_pid == pid && WIFEXITED(status)))
		    {
			wait_pid = pid;
			break;
		    }

		    /* Handle any X events, e.g. serving the clipboard. */
		    clip_update();

		    /* Wait for 1 to 10 msec. 1 is faster but gives the child
		     * less time. */
		    mch_delay(delay_msec, TRUE);
		    if (++delay_msec > 10)
			delay_msec = 10;
		}
	    }
# endif

	    /*
	     * Wait until our child has exited.
	     * Ignore wait() returning pids of other children and returning
	     * because of some signal like SIGWINCH.
	     * Don't wait if wait_pid was already set above, indicating the
	     * child already exited.
	     */
	    if (wait_pid != pid)
		wait_pid = wait4pid(pid, &status);

# ifdef FEAT_GUI
	    /* Close slave side of pty.  Only do this after the child has
	     * exited, otherwise the child may hang when it tries to write on
	     * the pty. */
	    if (pty_master_fd >= 0)
		close(pty_slave_fd);
# endif

	    /* Make sure the child that writes to the external program is
	     * dead. */
	    if (wpid > 0)
	    {
		kill(wpid, SIGKILL);
		wait4pid(wpid, NULL);
	    }

# ifdef FEAT_JOB_CHANNEL
	    --dont_check_job_ended;
# endif

	    /*
	     * Set to raw mode right now, otherwise a CTRL-C after
	     * catch_signals() will kill Vim.
	     */
	    if (tmode == TMODE_RAW)
		settmode(TMODE_RAW);
	    did_settmode = TRUE;
	    set_signals();

	    if (WIFEXITED(status))
	    {
		/* LINTED avoid "bitwise operation on signed value" */
		retval = WEXITSTATUS(status);
		if (retval != 0 && !emsg_silent)
		{
		    if (retval == EXEC_FAILED)
		    {
			msg_puts(_("\nCannot execute shell "));
			msg_outtrans(p_sh);
			msg_putchar('\n');
		    }
		    else if (!(options & SHELL_SILENT))
		    {
			msg_puts(_("\nshell returned "));
			msg_outnum((long)retval);
			msg_putchar('\n');
		    }
		}
	    }
	    else
		msg_puts(_("\nCommand terminated\n"));
	}
    }

error:
    if (!did_settmode)
	if (tmode == TMODE_RAW)
	    settmode(TMODE_RAW);	/* set to raw mode */
# ifdef FEAT_TITLE
    resettitle();
# endif
    vim_free(argv);
    vim_free(tofree1);
    vim_free(tofree2);

    return retval;
}
#endif /* USE_SYSTEM */

    int
mch_call_shell(
    char_u	*cmd,
    int		options)	/* SHELL_*, see vim.h */
{
#if defined(FEAT_GUI) && defined(FEAT_TERMINAL)
    if (gui.in_use && vim_strchr(p_go, GO_TERMINAL) != NULL)
	return mch_call_shell_terminal(cmd, options);
#endif
#ifdef USE_SYSTEM
    return mch_call_shell_system(cmd, options);
#else
    return mch_call_shell_fork(cmd, options);
#endif
}

#if defined(FEAT_JOB_CHANNEL) || defined(PROTO)
    void
mch_job_start(char **argv, job_T *job, jobopt_T *options, int is_terminal)
{
    pid_t	pid;
    int		fd_in[2] = {-1, -1};	/* for stdin */
    int		fd_out[2] = {-1, -1};	/* for stdout */
    int		fd_err[2] = {-1, -1};	/* for stderr */
    int		pty_master_fd = -1;
    int		pty_slave_fd = -1;
    channel_T	*channel = NULL;
    int		use_null_for_in = options->jo_io[PART_IN] == JIO_NULL;
    int		use_null_for_out = options->jo_io[PART_OUT] == JIO_NULL;
    int		use_null_for_err = options->jo_io[PART_ERR] == JIO_NULL;
    int		use_file_for_in = options->jo_io[PART_IN] == JIO_FILE;
    int		use_file_for_out = options->jo_io[PART_OUT] == JIO_FILE;
    int		use_file_for_err = options->jo_io[PART_ERR] == JIO_FILE;
    int		use_buffer_for_in = options->jo_io[PART_IN] == JIO_BUFFER;
    int		use_out_for_err = options->jo_io[PART_ERR] == JIO_OUT;
    SIGSET_DECL(curset)

    if (use_out_for_err && use_null_for_out)
	use_null_for_err = TRUE;

    /* default is to fail */
    job->jv_status = JOB_FAILED;

    if (options->jo_pty
	    && (!(use_file_for_in || use_null_for_in)
		|| !(use_file_for_in || use_null_for_out)
		|| !(use_out_for_err || use_file_for_err || use_null_for_err)))
    {
	open_pty(&pty_master_fd, &pty_slave_fd, &job->jv_tty_out);
	if (job->jv_tty_out != NULL)
	    job->jv_tty_in = vim_strsave(job->jv_tty_out);
    }

    /* TODO: without the channel feature connect the child to /dev/null? */
    /* Open pipes for stdin, stdout, stderr. */
    if (use_file_for_in)
    {
	char_u *fname = options->jo_io_name[PART_IN];

	fd_in[0] = mch_open((char *)fname, O_RDONLY, 0);
	if (fd_in[0] < 0)
	{
	    semsg(_(e_notopen), fname);
	    goto failed;
	}
    }
    else
	/* When writing buffer lines to the input don't use the pty, so that
	 * the pipe can be closed when all lines were written. */
	if (!use_null_for_in && (pty_master_fd < 0 || use_buffer_for_in)
							    && pipe(fd_in) < 0)
	    goto failed;

    if (use_file_for_out)
    {
	char_u *fname = options->jo_io_name[PART_OUT];

	fd_out[1] = mch_open((char *)fname, O_WRONLY | O_CREAT | O_TRUNC, 0644);
	if (fd_out[1] < 0)
	{
	    semsg(_(e_notopen), fname);
	    goto failed;
	}
    }
    else if (!use_null_for_out && pty_master_fd < 0 && pipe(fd_out) < 0)
	goto failed;

    if (use_file_for_err)
    {
	char_u *fname = options->jo_io_name[PART_ERR];

	fd_err[1] = mch_open((char *)fname, O_WRONLY | O_CREAT | O_TRUNC, 0600);
	if (fd_err[1] < 0)
	{
	    semsg(_(e_notopen), fname);
	    goto failed;
	}
    }
    else if (!use_out_for_err && !use_null_for_err
				      && pty_master_fd < 0 && pipe(fd_err) < 0)
	goto failed;

    if (!use_null_for_in || !use_null_for_out || !use_null_for_err)
    {
	if (options->jo_set & JO_CHANNEL)
	{
	    channel = options->jo_channel;
	    if (channel != NULL)
		++channel->ch_refcount;
	}
	else
	    channel = add_channel();
	if (channel == NULL)
	    goto failed;
	if (job->jv_tty_out != NULL)
	    ch_log(channel, "using pty %s on fd %d",
					       job->jv_tty_out, pty_master_fd);
    }

    BLOCK_SIGNALS(&curset);
    pid = fork();	/* maybe we should use vfork() */
    if (pid == -1)
    {
	/* failed to fork */
	UNBLOCK_SIGNALS(&curset);
	goto failed;
    }
    if (pid == 0)
    {
	int	null_fd = -1;
	int	stderr_works = TRUE;

	/* child */
	reset_signals();		/* handle signals normally */
	UNBLOCK_SIGNALS(&curset);

# ifdef FEAT_JOB_CHANNEL
	if (ch_log_active())
	    /* close the log file in the child */
	    ch_logfile((char_u *)"", (char_u *)"");
# endif

# ifdef HAVE_SETSID
	/* Create our own process group, so that the child and all its
	 * children can be kill()ed.  Don't do this when using pipes,
	 * because stdin is not a tty, we would lose /dev/tty. */
	(void)setsid();
# endif

# ifdef FEAT_TERMINAL
	if (options->jo_term_rows > 0)
	{
	    char *term = (char *)T_NAME;

#ifdef FEAT_GUI
	    if (term_is_gui(T_NAME))
		/* In the GUI 'term' is not what we want, use $TERM. */
		term = getenv("TERM");
#endif
	    /* Use 'term' or $TERM if it starts with "xterm", otherwise fall
	     * back to "xterm". */
	    if (term == NULL || *term == NUL || STRNCMP(term, "xterm", 5) != 0)
		term = "xterm";
	    set_child_environment(
		    (long)options->jo_term_rows,
		    (long)options->jo_term_cols,
		    term,
		    is_terminal);
	}
	else
# endif
	    set_default_child_environment(is_terminal);

	if (options->jo_env != NULL)
	{
	    dict_T	*dict = options->jo_env;
	    hashitem_T	*hi;
	    int		todo = (int)dict->dv_hashtab.ht_used;

	    for (hi = dict->dv_hashtab.ht_array; todo > 0; ++hi)
		if (!HASHITEM_EMPTY(hi))
		{
		    typval_T *item = &dict_lookup(hi)->di_tv;

		    vim_setenv((char_u*)hi->hi_key, tv_get_string(item));
		    --todo;
		}
	}

	if (use_null_for_in || use_null_for_out || use_null_for_err)
	{
	    null_fd = open("/dev/null", O_RDWR | O_EXTRA, 0);
	    if (null_fd < 0)
	    {
		perror("opening /dev/null failed");
		_exit(OPEN_NULL_FAILED);
	    }
	}

	if (pty_slave_fd >= 0)
	{
	    /* push stream discipline modules */
	    SetupSlavePTY(pty_slave_fd);
#  ifdef TIOCSCTTY
	    /* Try to become controlling tty (probably doesn't work,
	     * unless run by root) */
	    ioctl(pty_slave_fd, TIOCSCTTY, (char *)NULL);
#  endif
	}

	/* set up stdin for the child */
	close(0);
	if (use_null_for_in && null_fd >= 0)
	    vim_ignored = dup(null_fd);
	else if (fd_in[0] < 0)
	    vim_ignored = dup(pty_slave_fd);
	else
	    vim_ignored = dup(fd_in[0]);

	/* set up stderr for the child */
	close(2);
	if (use_null_for_err && null_fd >= 0)
	{
	    vim_ignored = dup(null_fd);
	    stderr_works = FALSE;
	}
	else if (use_out_for_err)
	    vim_ignored = dup(fd_out[1]);
	else if (fd_err[1] < 0)
	    vim_ignored = dup(pty_slave_fd);
	else
	    vim_ignored = dup(fd_err[1]);

	/* set up stdout for the child */
	close(1);
	if (use_null_for_out && null_fd >= 0)
	    vim_ignored = dup(null_fd);
	else if (fd_out[1] < 0)
	    vim_ignored = dup(pty_slave_fd);
	else
	    vim_ignored = dup(fd_out[1]);

	if (fd_in[0] >= 0)
	    close(fd_in[0]);
	if (fd_in[1] >= 0)
	    close(fd_in[1]);
	if (fd_out[0] >= 0)
	    close(fd_out[0]);
	if (fd_out[1] >= 0)
	    close(fd_out[1]);
	if (fd_err[0] >= 0)
	    close(fd_err[0]);
	if (fd_err[1] >= 0)
	    close(fd_err[1]);
	if (pty_master_fd >= 0)
	{
	    close(pty_master_fd); /* not used in the child */
	    close(pty_slave_fd);  /* was duped above */
	}

	if (null_fd >= 0)
	    close(null_fd);

	if (options->jo_cwd != NULL && mch_chdir((char *)options->jo_cwd) != 0)
	    _exit(EXEC_FAILED);

	/* See above for type of argv. */
	execvp(argv[0], argv);

	if (stderr_works)
	    perror("executing job failed");
# ifdef EXITFREE
	/* calling free_all_mem() here causes problems. Ignore valgrind
	 * reporting possibly leaked memory. */
# endif
	_exit(EXEC_FAILED);	    /* exec failed, return failure code */
    }

    /* parent */
    UNBLOCK_SIGNALS(&curset);

    job->jv_pid = pid;
    job->jv_status = JOB_STARTED;
    job->jv_channel = channel;  /* ch_refcount was set above */

    if (pty_master_fd >= 0)
	close(pty_slave_fd); /* not used in the parent */
    /* close child stdin, stdout and stderr */
    if (fd_in[0] >= 0)
	close(fd_in[0]);
    if (fd_out[1] >= 0)
	close(fd_out[1]);
    if (fd_err[1] >= 0)
	close(fd_err[1]);
    if (channel != NULL)
    {
	int in_fd = use_file_for_in || use_null_for_in
			? INVALID_FD : fd_in[1] < 0 ? pty_master_fd : fd_in[1];
	int out_fd = use_file_for_out || use_null_for_out
		      ? INVALID_FD : fd_out[0] < 0 ? pty_master_fd : fd_out[0];
	/* When using pty_master_fd only set it for stdout, do not duplicate it
	 * for stderr, it only needs to be read once. */
	int err_fd = use_out_for_err || use_file_for_err || use_null_for_err
		      ? INVALID_FD
		      : fd_err[0] >= 0
		         ? fd_err[0]
		         : (out_fd == pty_master_fd
				 ? INVALID_FD
				 : pty_master_fd);

	channel_set_pipes(channel, in_fd, out_fd, err_fd);
	channel_set_job(channel, job, options);
    }
    else
    {
	if (fd_in[1] >= 0)
	    close(fd_in[1]);
	if (fd_out[0] >= 0)
	    close(fd_out[0]);
	if (fd_err[0] >= 0)
	    close(fd_err[0]);
	if (pty_master_fd >= 0)
	    close(pty_master_fd);
    }

    /* success! */
    return;

failed:
    channel_unref(channel);
    if (fd_in[0] >= 0)
	close(fd_in[0]);
    if (fd_in[1] >= 0)
	close(fd_in[1]);
    if (fd_out[0] >= 0)
	close(fd_out[0]);
    if (fd_out[1] >= 0)
	close(fd_out[1]);
    if (fd_err[0] >= 0)
	close(fd_err[0]);
    if (fd_err[1] >= 0)
	close(fd_err[1]);
    if (pty_master_fd >= 0)
	close(pty_master_fd);
    if (pty_slave_fd >= 0)
	close(pty_slave_fd);
}

    char *
mch_job_status(job_T *job)
{
# ifdef HAVE_UNION_WAIT
    union wait	status;
# else
    int		status = -1;
# endif
    pid_t	wait_pid = 0;

# ifdef __NeXT__
    wait_pid = wait4(job->jv_pid, &status, WNOHANG, (struct rusage *)0);
# else
    wait_pid = waitpid(job->jv_pid, &status, WNOHANG);
# endif
    if (wait_pid == -1)
    {
	/* process must have exited */
	if (job->jv_status < JOB_ENDED)
	    ch_log(job->jv_channel, "Job no longer exists: %s",
							      strerror(errno));
	goto return_dead;
    }
    if (wait_pid == 0)
	return "run";
    if (WIFEXITED(status))
    {
	/* LINTED avoid "bitwise operation on signed value" */
	job->jv_exitval = WEXITSTATUS(status);
	if (job->jv_status < JOB_ENDED)
	    ch_log(job->jv_channel, "Job exited with %d", job->jv_exitval);
	goto return_dead;
    }
    if (WIFSIGNALED(status))
    {
	job->jv_exitval = -1;
	if (job->jv_status < JOB_ENDED)
	    ch_log(job->jv_channel, "Job terminated by a signal");
	goto return_dead;
    }
    return "run";

return_dead:
    if (job->jv_status < JOB_ENDED)
	job->jv_status = JOB_ENDED;
    return "dead";
}

    job_T *
mch_detect_ended_job(job_T *job_list)
{
# ifdef HAVE_UNION_WAIT
    union wait	status;
# else
    int		status = -1;
# endif
    pid_t	wait_pid = 0;
    job_T	*job;

# ifndef USE_SYSTEM
    /* Do not do this when waiting for a shell command to finish, we would get
     * the exit value here (and discard it), the exit value obtained there
     * would then be wrong.  */
    if (dont_check_job_ended > 0)
	return NULL;
# endif

# ifdef __NeXT__
    wait_pid = wait4(-1, &status, WNOHANG, (struct rusage *)0);
# else
    wait_pid = waitpid(-1, &status, WNOHANG);
# endif
    if (wait_pid <= 0)
	/* no process ended */
	return NULL;
    for (job = job_list; job != NULL; job = job->jv_next)
    {
	if (job->jv_pid == wait_pid)
	{
	    if (WIFEXITED(status))
		/* LINTED avoid "bitwise operation on signed value" */
		job->jv_exitval = WEXITSTATUS(status);
	    else if (WIFSIGNALED(status))
		job->jv_exitval = -1;
	    if (job->jv_status < JOB_ENDED)
	    {
		ch_log(job->jv_channel, "Job ended");
		job->jv_status = JOB_ENDED;
	    }
	    return job;
	}
    }
    return NULL;
}

/*
 * Send a (deadly) signal to "job".
 * Return FAIL if "how" is not a valid name.
 */
    int
mch_signal_job(job_T *job, char_u *how)
{
    int	    sig = -1;

    if (*how == NUL || STRCMP(how, "term") == 0)
	sig = SIGTERM;
    else if (STRCMP(how, "hup") == 0)
	sig = SIGHUP;
    else if (STRCMP(how, "quit") == 0)
	sig = SIGQUIT;
    else if (STRCMP(how, "int") == 0)
	sig = SIGINT;
    else if (STRCMP(how, "kill") == 0)
	sig = SIGKILL;
#ifdef SIGWINCH
    else if (STRCMP(how, "winch") == 0)
	sig = SIGWINCH;
#endif
    else if (isdigit(*how))
	sig = atoi((char *)how);
    else
	return FAIL;

    // Never kill ourselves!
    if (job->jv_pid != 0)
    {
	// TODO: have an option to only kill the process, not the group?
	kill(-job->jv_pid, sig);
	kill(job->jv_pid, sig);
    }

    return OK;
}

/*
 * Clear the data related to "job".
 */
    void
mch_clear_job(job_T *job)
{
    /* call waitpid because child process may become zombie */
# ifdef __NeXT__
    (void)wait4(job->jv_pid, NULL, WNOHANG, (struct rusage *)0);
# else
    (void)waitpid(job->jv_pid, NULL, WNOHANG);
# endif
}
#endif

#if defined(FEAT_TERMINAL) || defined(PROTO)
    int
mch_create_pty_channel(job_T *job, jobopt_T *options)
{
    int		pty_master_fd = -1;
    int		pty_slave_fd = -1;
    channel_T	*channel;

    open_pty(&pty_master_fd, &pty_slave_fd, &job->jv_tty_out);
    if (job->jv_tty_out != NULL)
	job->jv_tty_in = vim_strsave(job->jv_tty_out);
    close(pty_slave_fd);

    channel = add_channel();
    if (channel == NULL)
    {
	close(pty_master_fd);
	return FAIL;
    }
    if (job->jv_tty_out != NULL)
	ch_log(channel, "using pty %s on fd %d",
					       job->jv_tty_out, pty_master_fd);
    job->jv_channel = channel;  /* ch_refcount was set by add_channel() */
    channel->ch_keep_open = TRUE;

    /* Only set the pty_master_fd for stdout, do not duplicate it for stderr,
     * it only needs to be read once. */
    channel_set_pipes(channel, pty_master_fd, pty_master_fd, INVALID_FD);
    channel_set_job(channel, job, options);
    return OK;
}
#endif

/*
 * Check for CTRL-C typed by reading all available characters.
 * In cooked mode we should get SIGINT, no need to check.
 */
    void
mch_breakcheck(int force)
{
    if ((curr_tmode == TMODE_RAW || force)
			       && RealWaitForChar(read_cmd_fd, 0L, NULL, NULL))
	fill_input_buf(FALSE);
}

/*
 * Wait "msec" msec until a character is available from the mouse, keyboard,
 * from inbuf[].
 * "msec" == -1 will block forever.
 * Invokes timer callbacks when needed.
 * When "ignore_input" is TRUE even check for pending input when input is
 * already available.
 * "interrupted" (if not NULL) is set to TRUE when no character is available
 * but something else needs to be done.
 * Returns TRUE when a character is available.
 * When a GUI is being used, this will never get called -- webb
 */
    static int
WaitForChar(long msec, int *interrupted, int ignore_input)
{
#ifdef FEAT_TIMERS
    return ui_wait_for_chars_or_timer(
		    msec, WaitForCharOrMouse, interrupted, ignore_input) == OK;
#else
    return WaitForCharOrMouse(msec, interrupted, ignore_input);
#endif
}

/*
 * Wait "msec" msec until a character is available from the mouse or keyboard
 * or from inbuf[].
 * "msec" == -1 will block forever.
 * for "ignore_input" see WaitForCharOr().
 * "interrupted" (if not NULL) is set to TRUE when no character is available
 * but something else needs to be done.
 * When a GUI is being used, this will never get called -- webb
 */
    static int
WaitForCharOrMouse(long msec, int *interrupted, int ignore_input)
{
#ifdef FEAT_MOUSE_GPM
    int		gpm_process_wanted;
#endif
#ifdef FEAT_XCLIPBOARD
    int		rest;
#endif
    int		avail;

    if (!ignore_input && input_available())	    /* something in inbuf[] */
	return 1;

#if defined(FEAT_MOUSE_DEC)
    /* May need to query the mouse position. */
    if (WantQueryMouse)
    {
	WantQueryMouse = FALSE;
	mch_write((char_u *)IF_EB("\033[1'|", ESC_STR "[1'|"), 5);
    }
#endif

    /*
     * For FEAT_MOUSE_GPM and FEAT_XCLIPBOARD we loop here to process mouse
     * events.  This is a bit complicated, because they might both be defined.
     */
#if defined(FEAT_MOUSE_GPM) || defined(FEAT_XCLIPBOARD)
# ifdef FEAT_XCLIPBOARD
    rest = 0;
    if (do_xterm_trace())
	rest = msec;
# endif
    do
    {
# ifdef FEAT_XCLIPBOARD
	if (rest != 0)
	{
	    msec = XT_TRACE_DELAY;
	    if (rest >= 0 && rest < XT_TRACE_DELAY)
		msec = rest;
	    if (rest >= 0)
		rest -= msec;
	}
# endif
# ifdef FEAT_MOUSE_GPM
	gpm_process_wanted = 0;
	avail = RealWaitForChar(read_cmd_fd, msec,
					     &gpm_process_wanted, interrupted);
# else
	avail = RealWaitForChar(read_cmd_fd, msec, NULL, interrupted);
# endif
	if (!avail)
	{
	    if (!ignore_input && input_available())
		return 1;
# ifdef FEAT_XCLIPBOARD
	    if (rest == 0 || !do_xterm_trace())
# endif
		break;
	}
    }
    while (FALSE
# ifdef FEAT_MOUSE_GPM
	   || (gpm_process_wanted && mch_gpm_process() == 0)
# endif
# ifdef FEAT_XCLIPBOARD
	   || (!avail && rest != 0)
# endif
	  )
	;

#else
    avail = RealWaitForChar(read_cmd_fd, msec, NULL, interrupted);
#endif
    return avail;
}

#ifndef VMS
/*
 * Wait "msec" msec until a character is available from file descriptor "fd".
 * "msec" == 0 will check for characters once.
 * "msec" == -1 will block until a character is available.
 * When a GUI is being used, this will not be used for input -- webb
 * Or when a Linux GPM mouse event is waiting.
 * Or when a clientserver message is on the queue.
 * "interrupted" (if not NULL) is set to TRUE when no character is available
 * but something else needs to be done.
 */
#if defined(__BEOS__)
    int
#else
    static int
#endif
RealWaitForChar(int fd, long msec, int *check_for_gpm UNUSED, int *interrupted)
{
    int		ret;
    int		result;
#if defined(FEAT_XCLIPBOARD) || defined(USE_XSMP) || defined(FEAT_MZSCHEME)
    static int	busy = FALSE;

    /* May retry getting characters after an event was handled. */
# define MAY_LOOP

# ifdef ELAPSED_FUNC
    /* Remember at what time we started, so that we know how much longer we
     * should wait after being interrupted. */
    long	start_msec = msec;
    elapsed_T	start_tv;

    if (msec > 0)
	ELAPSED_INIT(start_tv);
# endif

    /* Handle being called recursively.  This may happen for the session
     * manager stuff, it may save the file, which does a breakcheck. */
    if (busy)
	return 0;
#endif

#ifdef MAY_LOOP
    for (;;)
#endif
    {
#ifdef MAY_LOOP
	int		finished = TRUE; /* default is to 'loop' just once */
# ifdef FEAT_MZSCHEME
	int		mzquantum_used = FALSE;
# endif
#endif
#ifndef HAVE_SELECT
			/* each channel may use in, out and err */
	struct pollfd   fds[6 + 3 * MAX_OPEN_CHANNELS];
	int		nfd;
# ifdef FEAT_XCLIPBOARD
	int		xterm_idx = -1;
# endif
# ifdef FEAT_MOUSE_GPM
	int		gpm_idx = -1;
# endif
# ifdef USE_XSMP
	int		xsmp_idx = -1;
# endif
	int		towait = (int)msec;

# ifdef FEAT_MZSCHEME
	mzvim_check_threads();
	if (mzthreads_allowed() && p_mzq > 0 && (msec < 0 || msec > p_mzq))
	{
	    towait = (int)p_mzq;    /* don't wait longer than 'mzquantum' */
	    mzquantum_used = TRUE;
	}
# endif
	fds[0].fd = fd;
	fds[0].events = POLLIN;
	nfd = 1;

# ifdef FEAT_XCLIPBOARD
	may_restore_clipboard();
	if (xterm_Shell != (Widget)0)
	{
	    xterm_idx = nfd;
	    fds[nfd].fd = ConnectionNumber(xterm_dpy);
	    fds[nfd].events = POLLIN;
	    nfd++;
	}
# endif
# ifdef FEAT_MOUSE_GPM
	if (check_for_gpm != NULL && gpm_flag && gpm_fd >= 0)
	{
	    gpm_idx = nfd;
	    fds[nfd].fd = gpm_fd;
	    fds[nfd].events = POLLIN;
	    nfd++;
	}
# endif
# ifdef USE_XSMP
	if (xsmp_icefd != -1)
	{
	    xsmp_idx = nfd;
	    fds[nfd].fd = xsmp_icefd;
	    fds[nfd].events = POLLIN;
	    nfd++;
	}
# endif
#ifdef FEAT_JOB_CHANNEL
	nfd = channel_poll_setup(nfd, &fds, &towait);
#endif
	if (interrupted != NULL)
	    *interrupted = FALSE;

	ret = poll(fds, nfd, towait);

	result = ret > 0 && (fds[0].revents & POLLIN);
	if (result == 0 && interrupted != NULL && ret > 0)
	    *interrupted = TRUE;

# ifdef FEAT_MZSCHEME
	if (ret == 0 && mzquantum_used)
	    /* MzThreads scheduling is required and timeout occurred */
	    finished = FALSE;
# endif

# ifdef FEAT_XCLIPBOARD
	if (xterm_Shell != (Widget)0 && (fds[xterm_idx].revents & POLLIN))
	{
	    xterm_update();      /* Maybe we should hand out clipboard */
	    if (--ret == 0 && !input_available())
		/* Try again */
		finished = FALSE;
	}
# endif
# ifdef FEAT_MOUSE_GPM
	if (gpm_idx >= 0 && (fds[gpm_idx].revents & POLLIN))
	{
	    *check_for_gpm = 1;
	}
# endif
# ifdef USE_XSMP
	if (xsmp_idx >= 0 && (fds[xsmp_idx].revents & (POLLIN | POLLHUP)))
	{
	    if (fds[xsmp_idx].revents & POLLIN)
	    {
		busy = TRUE;
		xsmp_handle_requests();
		busy = FALSE;
	    }
	    else if (fds[xsmp_idx].revents & POLLHUP)
	    {
		if (p_verbose > 0)
		    verb_msg(_("XSMP lost ICE connection"));
		xsmp_close();
	    }
	    if (--ret == 0)
		finished = FALSE;	/* Try again */
	}
# endif
#ifdef FEAT_JOB_CHANNEL
	/* also call when ret == 0, we may be polling a keep-open channel */
	if (ret >= 0)
	    ret = channel_poll_check(ret, &fds);
#endif

#else /* HAVE_SELECT */

	struct timeval  tv;
	struct timeval	*tvp;
	// These are static because they can take 8 Kbyte each and cause the
	// signal stack to run out with -O3.
	static fd_set	rfds, wfds, efds;
	int		maxfd;
	long		towait = msec;

# ifdef FEAT_MZSCHEME
	mzvim_check_threads();
	if (mzthreads_allowed() && p_mzq > 0 && (msec < 0 || msec > p_mzq))
	{
	    towait = p_mzq;	/* don't wait longer than 'mzquantum' */
	    mzquantum_used = TRUE;
	}
# endif

	if (towait >= 0)
	{
	    tv.tv_sec = towait / 1000;
	    tv.tv_usec = (towait % 1000) * (1000000/1000);
	    tvp = &tv;
	}
	else
	    tvp = NULL;

	/*
	 * Select on ready for reading and exceptional condition (end of file).
	 */
select_eintr:
	FD_ZERO(&rfds);
	FD_ZERO(&wfds);
	FD_ZERO(&efds);
	FD_SET(fd, &rfds);
# if !defined(__QNX__) && !defined(__CYGWIN32__)
	/* For QNX select() always returns 1 if this is set.  Why? */
	FD_SET(fd, &efds);
# endif
	maxfd = fd;

# ifdef FEAT_XCLIPBOARD
	may_restore_clipboard();
	if (xterm_Shell != (Widget)0)
	{
	    FD_SET(ConnectionNumber(xterm_dpy), &rfds);
	    if (maxfd < ConnectionNumber(xterm_dpy))
		maxfd = ConnectionNumber(xterm_dpy);

	    /* An event may have already been read but not handled.  In
	     * particulary, XFlush may cause this. */
	    xterm_update();
	}
# endif
# ifdef FEAT_MOUSE_GPM
	if (check_for_gpm != NULL && gpm_flag && gpm_fd >= 0)
	{
	    FD_SET(gpm_fd, &rfds);
	    FD_SET(gpm_fd, &efds);
	    if (maxfd < gpm_fd)
		maxfd = gpm_fd;
	}
# endif
# ifdef USE_XSMP
	if (xsmp_icefd != -1)
	{
	    FD_SET(xsmp_icefd, &rfds);
	    FD_SET(xsmp_icefd, &efds);
	    if (maxfd < xsmp_icefd)
		maxfd = xsmp_icefd;
	}
# endif
# ifdef FEAT_JOB_CHANNEL
	maxfd = channel_select_setup(maxfd, &rfds, &wfds, &tv, &tvp);
# endif
	if (interrupted != NULL)
	    *interrupted = FALSE;

	ret = select(maxfd + 1, SELECT_TYPE_ARG234 &rfds,
		      SELECT_TYPE_ARG234 &wfds, SELECT_TYPE_ARG234 &efds, tvp);
	result = ret > 0 && FD_ISSET(fd, &rfds);
	if (result)
	    --ret;
	else if (interrupted != NULL && ret > 0)
	    *interrupted = TRUE;

# ifdef EINTR
	if (ret == -1 && errno == EINTR)
	{
	    /* Check whether window has been resized, EINTR may be caused by
	     * SIGWINCH. */
	    if (do_resize)
		handle_resize();

	    /* Interrupted by a signal, need to try again.  We ignore msec
	     * here, because we do want to check even after a timeout if
	     * characters are available.  Needed for reading output of an
	     * external command after the process has finished. */
	    goto select_eintr;
	}
# endif
# ifdef __TANDEM
	if (ret == -1 && errno == ENOTSUP)
	{
	    FD_ZERO(&rfds);
	    FD_ZERO(&efds);
	    ret = 0;
	}
# endif
# ifdef FEAT_MZSCHEME
	if (ret == 0 && mzquantum_used)
	    /* loop if MzThreads must be scheduled and timeout occurred */
	    finished = FALSE;
# endif

# ifdef FEAT_XCLIPBOARD
	if (ret > 0 && xterm_Shell != (Widget)0
		&& FD_ISSET(ConnectionNumber(xterm_dpy), &rfds))
	{
	    xterm_update();	      /* Maybe we should hand out clipboard */
	    /* continue looping when we only got the X event and the input
	     * buffer is empty */
	    if (--ret == 0 && !input_available())
	    {
		/* Try again */
		finished = FALSE;
	    }
	}
# endif
# ifdef FEAT_MOUSE_GPM
	if (ret > 0 && gpm_flag && check_for_gpm != NULL && gpm_fd >= 0)
	{
	    if (FD_ISSET(gpm_fd, &efds))
		gpm_close();
	    else if (FD_ISSET(gpm_fd, &rfds))
		*check_for_gpm = 1;
	}
# endif
# ifdef USE_XSMP
	if (ret > 0 && xsmp_icefd != -1)
	{
	    if (FD_ISSET(xsmp_icefd, &efds))
	    {
		if (p_verbose > 0)
		    verb_msg(_("XSMP lost ICE connection"));
		xsmp_close();
		if (--ret == 0)
		    finished = FALSE;   /* keep going if event was only one */
	    }
	    else if (FD_ISSET(xsmp_icefd, &rfds))
	    {
		busy = TRUE;
		xsmp_handle_requests();
		busy = FALSE;
		if (--ret == 0)
		    finished = FALSE;   /* keep going if event was only one */
	    }
	}
# endif
#ifdef FEAT_JOB_CHANNEL
	/* also call when ret == 0, we may be polling a keep-open channel */
	if (ret >= 0)
	    ret = channel_select_check(ret, &rfds, &wfds);
#endif

#endif /* HAVE_SELECT */

#ifdef MAY_LOOP
	if (finished || msec == 0)
	    break;

# ifdef FEAT_CLIENTSERVER
	if (server_waiting())
	    break;
# endif

	/* We're going to loop around again, find out for how long */
	if (msec > 0)
	{
# ifdef ELAPSED_FUNC
	    /* Compute remaining wait time. */
	    msec = start_msec - ELAPSED_FUNC(start_tv);
# else
	    /* Guess we got interrupted halfway. */
	    msec = msec / 2;
# endif
	    if (msec <= 0)
		break;	/* waited long enough */
	}
#endif
    }

    return result;
}

#ifndef NO_EXPANDPATH
/*
 * Expand a path into all matching files and/or directories.  Handles "*",
 * "?", "[a-z]", "**", etc.
 * "path" has backslashes before chars that are not to be expanded.
 * Returns the number of matches found.
 */
    int
mch_expandpath(
    garray_T	*gap,
    char_u	*path,
    int		flags)		/* EW_* flags */
{
    return unix_expandpath(gap, path, 0, flags, FALSE);
}
#endif

/*
 * mch_expand_wildcards() - this code does wild-card pattern matching using
 * the shell
 *
 * return OK for success, FAIL for error (you may lose some memory) and put
 * an error message in *file.
 *
 * num_pat is number of input patterns
 * pat is array of pointers to input patterns
 * num_file is pointer to number of matched file names
 * file is pointer to array of pointers to matched file names
 */

#ifndef SEEK_SET
# define SEEK_SET 0
#endif
#ifndef SEEK_END
# define SEEK_END 2
#endif

#define SHELL_SPECIAL (char_u *)"\t \"&'$;<>()\\|"

    int
mch_expand_wildcards(
    int		   num_pat,
    char_u	 **pat,
    int		  *num_file,
    char_u	***file,
    int		   flags)	/* EW_* flags */
{
    int		i;
    size_t	len;
    long	llen;
    char_u	*p;
    int		dir;

    /*
     * This is the non-OS/2 implementation (really Unix).
     */
    int		j;
    char_u	*tempname;
    char_u	*command;
    FILE	*fd;
    char_u	*buffer;
#define STYLE_ECHO	0	/* use "echo", the default */
#define STYLE_GLOB	1	/* use "glob", for csh */
#define STYLE_VIMGLOB	2	/* use "vimglob", for Posix sh */
#define STYLE_PRINT	3	/* use "print -N", for zsh */
#define STYLE_BT	4	/* `cmd` expansion, execute the pattern
				 * directly */
    int		shell_style = STYLE_ECHO;
    int		check_spaces;
    static int	did_find_nul = FALSE;
    int		ampersent = FALSE;
		/* vimglob() function to define for Posix shell */
    static char *sh_vimglob_func = "vimglob() { while [ $# -ge 1 ]; do echo \"$1\"; shift; done }; vimglob >";

    *num_file = 0;	/* default: no files found */
    *file = NULL;

    /*
     * If there are no wildcards, just copy the names to allocated memory.
     * Saves a lot of time, because we don't have to start a new shell.
     */
    if (!have_wildcard(num_pat, pat))
	return save_patterns(num_pat, pat, num_file, file);

# ifdef HAVE_SANDBOX
    /* Don't allow any shell command in the sandbox. */
    if (sandbox != 0 && check_secure())
	return FAIL;
# endif

    /*
     * Don't allow the use of backticks in secure and restricted mode.
     */
    if (secure || restricted)
	for (i = 0; i < num_pat; ++i)
	    if (vim_strchr(pat[i], '`') != NULL
		    && (check_restricted() || check_secure()))
		return FAIL;

    /*
     * get a name for the temp file
     */
    if ((tempname = vim_tempname('o', FALSE)) == NULL)
    {
	emsg(_(e_notmp));
	return FAIL;
    }

    /*
     * Let the shell expand the patterns and write the result into the temp
     * file.
     * STYLE_BT:	NL separated
     *	    If expanding `cmd` execute it directly.
     * STYLE_GLOB:	NUL separated
     *	    If we use *csh, "glob" will work better than "echo".
     * STYLE_PRINT:	NL or NUL separated
     *	    If we use *zsh, "print -N" will work better than "glob".
     * STYLE_VIMGLOB:	NL separated
     *	    If we use *sh*, we define "vimglob()".
     * STYLE_ECHO:	space separated.
     *	    A shell we don't know, stay safe and use "echo".
     */
    if (num_pat == 1 && *pat[0] == '`'
	    && (len = STRLEN(pat[0])) > 2
	    && *(pat[0] + len - 1) == '`')
	shell_style = STYLE_BT;
    else if ((len = STRLEN(p_sh)) >= 3)
    {
	if (STRCMP(p_sh + len - 3, "csh") == 0)
	    shell_style = STYLE_GLOB;
	else if (STRCMP(p_sh + len - 3, "zsh") == 0)
	    shell_style = STYLE_PRINT;
    }
    if (shell_style == STYLE_ECHO && strstr((char *)gettail(p_sh),
								"sh") != NULL)
	shell_style = STYLE_VIMGLOB;

    /* Compute the length of the command.  We need 2 extra bytes: for the
     * optional '&' and for the NUL.
     * Worst case: "unset nonomatch; print -N >" plus two is 29 */
    len = STRLEN(tempname) + 29;
    if (shell_style == STYLE_VIMGLOB)
	len += STRLEN(sh_vimglob_func);

    for (i = 0; i < num_pat; ++i)
    {
	/* Count the length of the patterns in the same way as they are put in
	 * "command" below. */
#ifdef USE_SYSTEM
	len += STRLEN(pat[i]) + 3;	/* add space and two quotes */
#else
	++len;				/* add space */
	for (j = 0; pat[i][j] != NUL; ++j)
	{
	    if (vim_strchr(SHELL_SPECIAL, pat[i][j]) != NULL)
		++len;		/* may add a backslash */
	    ++len;
	}
#endif
    }
    command = alloc(len);
    if (command == NULL)
    {
	/* out of memory */
	vim_free(tempname);
	return FAIL;
    }

    /*
     * Build the shell command:
     * - Set $nonomatch depending on EW_NOTFOUND (hopefully the shell
     *	 recognizes this).
     * - Add the shell command to print the expanded names.
     * - Add the temp file name.
     * - Add the file name patterns.
     */
    if (shell_style == STYLE_BT)
    {
	/* change `command; command& ` to (command; command ) */
	STRCPY(command, "(");
	STRCAT(command, pat[0] + 1);		/* exclude first backtick */
	p = command + STRLEN(command) - 1;
	*p-- = ')';				/* remove last backtick */
	while (p > command && VIM_ISWHITE(*p))
	    --p;
	if (*p == '&')				/* remove trailing '&' */
	{
	    ampersent = TRUE;
	    *p = ' ';
	}
	STRCAT(command, ">");
    }
    else
    {
	if (flags & EW_NOTFOUND)
	    STRCPY(command, "set nonomatch; ");
	else
	    STRCPY(command, "unset nonomatch; ");
	if (shell_style == STYLE_GLOB)
	    STRCAT(command, "glob >");
	else if (shell_style == STYLE_PRINT)
	    STRCAT(command, "print -N >");
	else if (shell_style == STYLE_VIMGLOB)
	    STRCAT(command, sh_vimglob_func);
	else
	    STRCAT(command, "echo >");
    }

    STRCAT(command, tempname);

    if (shell_style != STYLE_BT)
	for (i = 0; i < num_pat; ++i)
	{
	    /* When using system() always add extra quotes, because the shell
	     * is started twice.  Otherwise put a backslash before special
	     * characters, except inside ``. */
#ifdef USE_SYSTEM
	    STRCAT(command, " \"");
	    STRCAT(command, pat[i]);
	    STRCAT(command, "\"");
#else
	    int intick = FALSE;

	    p = command + STRLEN(command);
	    *p++ = ' ';
	    for (j = 0; pat[i][j] != NUL; ++j)
	    {
		if (pat[i][j] == '`')
		    intick = !intick;
		else if (pat[i][j] == '\\' && pat[i][j + 1] != NUL)
		{
		    /* Remove a backslash, take char literally.  But keep
		     * backslash inside backticks, before a special character
		     * and before a backtick. */
		    if (intick
			  || vim_strchr(SHELL_SPECIAL, pat[i][j + 1]) != NULL
			  || pat[i][j + 1] == '`')
			*p++ = '\\';
		    ++j;
		}
		else if (!intick
			 && ((flags & EW_KEEPDOLLAR) == 0 || pat[i][j] != '$')
			      && vim_strchr(SHELL_SPECIAL, pat[i][j]) != NULL)
		    /* Put a backslash before a special character, but not
		     * when inside ``. And not for $var when EW_KEEPDOLLAR is
		     * set. */
		    *p++ = '\\';

		/* Copy one character. */
		*p++ = pat[i][j];
	    }
	    *p = NUL;
#endif
	}
    if (flags & EW_SILENT)
	show_shell_mess = FALSE;
    if (ampersent)
	STRCAT(command, "&");		/* put the '&' after the redirection */

    /*
     * Using zsh -G: If a pattern has no matches, it is just deleted from
     * the argument list, otherwise zsh gives an error message and doesn't
     * expand any other pattern.
     */
    if (shell_style == STYLE_PRINT)
	extra_shell_arg = (char_u *)"-G";   /* Use zsh NULL_GLOB option */

    /*
     * If we use -f then shell variables set in .cshrc won't get expanded.
     * vi can do it, so we will too, but it is only necessary if there is a "$"
     * in one of the patterns, otherwise we can still use the fast option.
     */
    else if (shell_style == STYLE_GLOB && !have_dollars(num_pat, pat))
	extra_shell_arg = (char_u *)"-f";	/* Use csh fast option */

    /*
     * execute the shell command
     */
    i = call_shell(command, SHELL_EXPAND | SHELL_SILENT);

    /* When running in the background, give it some time to create the temp
     * file, but don't wait for it to finish. */
    if (ampersent)
	mch_delay(10L, TRUE);

    extra_shell_arg = NULL;		/* cleanup */
    show_shell_mess = TRUE;
    vim_free(command);

    if (i != 0)				/* mch_call_shell() failed */
    {
	mch_remove(tempname);
	vim_free(tempname);
	/*
	 * With interactive completion, the error message is not printed.
	 * However with USE_SYSTEM, I don't know how to turn off error messages
	 * from the shell, so screen may still get messed up -- webb.
	 */
#ifndef USE_SYSTEM
	if (!(flags & EW_SILENT))
#endif
	{
	    redraw_later_clear();	/* probably messed up screen */
	    msg_putchar('\n');		/* clear bottom line quickly */
	    cmdline_row = Rows - 1;	/* continue on last line */
#ifdef USE_SYSTEM
	    if (!(flags & EW_SILENT))
#endif
	    {
		msg(_(e_wildexpand));
		msg_start();		/* don't overwrite this message */
	    }
	}
	/* If a `cmd` expansion failed, don't list `cmd` as a match, even when
	 * EW_NOTFOUND is given */
	if (shell_style == STYLE_BT)
	    return FAIL;
	goto notfound;
    }

    /*
     * read the names from the file into memory
     */
    fd = fopen((char *)tempname, READBIN);
    if (fd == NULL)
    {
	/* Something went wrong, perhaps a file name with a special char. */
	if (!(flags & EW_SILENT))
	{
	    msg(_(e_wildexpand));
	    msg_start();		/* don't overwrite this message */
	}
	vim_free(tempname);
	goto notfound;
    }
    fseek(fd, 0L, SEEK_END);
    llen = ftell(fd);			/* get size of temp file */
    fseek(fd, 0L, SEEK_SET);
    if (llen < 0)
	/* just in case ftell() would fail */
	buffer = NULL;
    else
	buffer = alloc(llen + 1);
    if (buffer == NULL)
    {
	/* out of memory */
	mch_remove(tempname);
	vim_free(tempname);
	fclose(fd);
	return FAIL;
    }
    len = llen;
    i = fread((char *)buffer, 1, len, fd);
    fclose(fd);
    mch_remove(tempname);
    if (i != (int)len)
    {
	/* unexpected read error */
	semsg(_(e_notread), tempname);
	vim_free(tempname);
	vim_free(buffer);
	return FAIL;
    }
    vim_free(tempname);

# if defined(__CYGWIN__) || defined(__CYGWIN32__)
    /* Translate <CR><NL> into <NL>.  Caution, buffer may contain NUL. */
    p = buffer;
    for (i = 0; i < (int)len; ++i)
	if (!(buffer[i] == CAR && buffer[i + 1] == NL))
	    *p++ = buffer[i];
    len = p - buffer;
# endif


    /* file names are separated with Space */
    if (shell_style == STYLE_ECHO)
    {
	buffer[len] = '\n';		/* make sure the buffer ends in NL */
	p = buffer;
	for (i = 0; *p != '\n'; ++i)	/* count number of entries */
	{
	    while (*p != ' ' && *p != '\n')
		++p;
	    p = skipwhite(p);		/* skip to next entry */
	}
    }
    /* file names are separated with NL */
    else if (shell_style == STYLE_BT || shell_style == STYLE_VIMGLOB)
    {
	buffer[len] = NUL;		/* make sure the buffer ends in NUL */
	p = buffer;
	for (i = 0; *p != NUL; ++i)	/* count number of entries */
	{
	    while (*p != '\n' && *p != NUL)
		++p;
	    if (*p != NUL)
		++p;
	    p = skipwhite(p);		/* skip leading white space */
	}
    }
    /* file names are separated with NUL */
    else
    {
	/*
	 * Some versions of zsh use spaces instead of NULs to separate
	 * results.  Only do this when there is no NUL before the end of the
	 * buffer, otherwise we would never be able to use file names with
	 * embedded spaces when zsh does use NULs.
	 * When we found a NUL once, we know zsh is OK, set did_find_nul and
	 * don't check for spaces again.
	 */
	check_spaces = FALSE;
	if (shell_style == STYLE_PRINT && !did_find_nul)
	{
	    /* If there is a NUL, set did_find_nul, else set check_spaces */
	    buffer[len] = NUL;
	    if (len && (int)STRLEN(buffer) < (int)len)
		did_find_nul = TRUE;
	    else
		check_spaces = TRUE;
	}

	/*
	 * Make sure the buffer ends with a NUL.  For STYLE_PRINT there
	 * already is one, for STYLE_GLOB it needs to be added.
	 */
	if (len && buffer[len - 1] == NUL)
	    --len;
	else
	    buffer[len] = NUL;
	i = 0;
	for (p = buffer; p < buffer + len; ++p)
	    if (*p == NUL || (*p == ' ' && check_spaces))   /* count entry */
	    {
		++i;
		*p = NUL;
	    }
	if (len)
	    ++i;			/* count last entry */
    }
    if (i == 0)
    {
	/*
	 * Can happen when using /bin/sh and typing ":e $NO_SUCH_VAR^I".
	 * /bin/sh will happily expand it to nothing rather than returning an
	 * error; and hey, it's good to check anyway -- webb.
	 */
	vim_free(buffer);
	goto notfound;
    }
    *num_file = i;
    *file = (char_u **)alloc(sizeof(char_u *) * i);
    if (*file == NULL)
    {
	/* out of memory */
	vim_free(buffer);
	return FAIL;
    }

    /*
     * Isolate the individual file names.
     */
    p = buffer;
    for (i = 0; i < *num_file; ++i)
    {
	(*file)[i] = p;
	/* Space or NL separates */
	if (shell_style == STYLE_ECHO || shell_style == STYLE_BT
					      || shell_style == STYLE_VIMGLOB)
	{
	    while (!(shell_style == STYLE_ECHO && *p == ' ')
						   && *p != '\n' && *p != NUL)
		++p;
	    if (p == buffer + len)		/* last entry */
		*p = NUL;
	    else
	    {
		*p++ = NUL;
		p = skipwhite(p);		/* skip to next entry */
	    }
	}
	else		/* NUL separates */
	{
	    while (*p && p < buffer + len)	/* skip entry */
		++p;
	    ++p;				/* skip NUL */
	}
    }

    /*
     * Move the file names to allocated memory.
     */
    for (j = 0, i = 0; i < *num_file; ++i)
    {
	/* Require the files to exist.	Helps when using /bin/sh */
	if (!(flags & EW_NOTFOUND) && mch_getperm((*file)[i]) < 0)
	    continue;

	/* check if this entry should be included */
	dir = (mch_isdir((*file)[i]));
	if ((dir && !(flags & EW_DIR)) || (!dir && !(flags & EW_FILE)))
	    continue;

	/* Skip files that are not executable if we check for that. */
	if (!dir && (flags & EW_EXEC)
		    && !mch_can_exe((*file)[i], NULL, !(flags & EW_SHELLCMD)))
	    continue;

	p = alloc((unsigned)(STRLEN((*file)[i]) + 1 + dir));
	if (p)
	{
	    STRCPY(p, (*file)[i]);
	    if (dir)
		add_pathsep(p);	    /* add '/' to a directory name */
	    (*file)[j++] = p;
	}
    }
    vim_free(buffer);
    *num_file = j;

    if (*num_file == 0)	    /* rejected all entries */
    {
	VIM_CLEAR(*file);
	goto notfound;
    }

    return OK;

notfound:
    if (flags & EW_NOTFOUND)
	return save_patterns(num_pat, pat, num_file, file);
    return FAIL;
}

#endif /* VMS */

    static int
save_patterns(
    int		num_pat,
    char_u	**pat,
    int		*num_file,
    char_u	***file)
{
    int		i;
    char_u	*s;

    *file = (char_u **)alloc(num_pat * sizeof(char_u *));
    if (*file == NULL)
	return FAIL;
    for (i = 0; i < num_pat; i++)
    {
	s = vim_strsave(pat[i]);
	if (s != NULL)
	    /* Be compatible with expand_filename(): halve the number of
	     * backslashes. */
	    backslash_halve(s);
	(*file)[i] = s;
    }
    *num_file = num_pat;
    return OK;
}

/*
 * Return TRUE if the string "p" contains a wildcard that mch_expandpath() can
 * expand.
 */
    int
mch_has_exp_wildcard(char_u *p)
{
    for ( ; *p; MB_PTR_ADV(p))
    {
	if (*p == '\\' && p[1] != NUL)
	    ++p;
	else
	    if (vim_strchr((char_u *)
#ifdef VMS
				    "*?%"
#else
				    "*?[{'"
#endif
						, *p) != NULL)
	    return TRUE;
    }
    return FALSE;
}

/*
 * Return TRUE if the string "p" contains a wildcard.
 * Don't recognize '~' at the end as a wildcard.
 */
    int
mch_has_wildcard(char_u *p)
{
    for ( ; *p; MB_PTR_ADV(p))
    {
	if (*p == '\\' && p[1] != NUL)
	    ++p;
	else
	    if (vim_strchr((char_u *)
#ifdef VMS
				    "*?%$"
#else
				    "*?[{`'$"
#endif
						, *p) != NULL
		|| (*p == '~' && p[1] != NUL))
	    return TRUE;
    }
    return FALSE;
}

    static int
have_wildcard(int num, char_u **file)
{
    int	    i;

    for (i = 0; i < num; i++)
	if (mch_has_wildcard(file[i]))
	    return 1;
    return 0;
}

    static int
have_dollars(int num, char_u **file)
{
    int	    i;

    for (i = 0; i < num; i++)
	if (vim_strchr(file[i], '$') != NULL)
	    return TRUE;
    return FALSE;
}

#if !defined(HAVE_RENAME) || defined(PROTO)
/*
 * Scaled-down version of rename(), which is missing in Xenix.
 * This version can only move regular files and will fail if the
 * destination exists.
 */
    int
mch_rename(const char *src, const char *dest)
{
    struct stat	    st;

    if (stat(dest, &st) >= 0)	    /* fail if destination exists */
	return -1;
    if (link(src, dest) != 0)	    /* link file to new name */
	return -1;
    if (mch_remove(src) == 0)	    /* delete link to old name */
	return 0;
    return -1;
}
#endif /* !HAVE_RENAME */

#ifdef FEAT_MOUSE_GPM
/*
 * Initializes connection with gpm (if it isn't already opened)
 * Return 1 if succeeded (or connection already opened), 0 if failed
 */
    static int
gpm_open(void)
{
    static Gpm_Connect gpm_connect; /* Must it be kept till closing ? */

    if (!gpm_flag)
    {
	gpm_connect.eventMask = (GPM_UP | GPM_DRAG | GPM_DOWN);
	gpm_connect.defaultMask = ~GPM_HARD;
	/* Default handling for mouse move*/
	gpm_connect.minMod = 0; /* Handle any modifier keys */
	gpm_connect.maxMod = 0xffff;
	if (Gpm_Open(&gpm_connect, 0) > 0)
	{
	    /* gpm library tries to handling TSTP causes
	     * problems. Anyways, we close connection to Gpm whenever
	     * we are going to suspend or starting an external process
	     * so we shouldn't  have problem with this
	     */
# ifdef SIGTSTP
	    signal(SIGTSTP, restricted ? SIG_IGN : SIG_DFL);
# endif
	    return 1; /* succeed */
	}
	if (gpm_fd == -2)
	    Gpm_Close(); /* We don't want to talk to xterm via gpm */
	return 0;
    }
    return 1; /* already open */
}

/*
 * Closes connection to gpm
 */
    static void
gpm_close(void)
{
    if (gpm_flag && gpm_fd >= 0) /* if Open */
	Gpm_Close();
}

/* Reads gpm event and adds special keys to input buf. Returns length of
 * generated key sequence.
 * This function is styled after gui_send_mouse_event().
 */
    static int
mch_gpm_process(void)
{
    int			button;
    static Gpm_Event	gpm_event;
    char_u		string[6];
    int_u		vim_modifiers;
    int			row,col;
    unsigned char	buttons_mask;
    unsigned char	gpm_modifiers;
    static unsigned char old_buttons = 0;

    Gpm_GetEvent(&gpm_event);

#ifdef FEAT_GUI
    /* Don't put events in the input queue now. */
    if (hold_gui_events)
	return 0;
#endif

    row = gpm_event.y - 1;
    col = gpm_event.x - 1;

    string[0] = ESC; /* Our termcode */
    string[1] = 'M';
    string[2] = 'G';
    switch (GPM_BARE_EVENTS(gpm_event.type))
    {
	case GPM_DRAG:
	    string[3] = MOUSE_DRAG;
	    break;
	case GPM_DOWN:
	    buttons_mask = gpm_event.buttons & ~old_buttons;
	    old_buttons = gpm_event.buttons;
	    switch (buttons_mask)
	    {
		case GPM_B_LEFT:
		    button = MOUSE_LEFT;
		    break;
		case GPM_B_MIDDLE:
		    button = MOUSE_MIDDLE;
		    break;
		case GPM_B_RIGHT:
		    button = MOUSE_RIGHT;
		    break;
		default:
		    return 0;
		    /*Don't know what to do. Can more than one button be
		     * reported in one event? */
	    }
	    string[3] = (char_u)(button | 0x20);
	    SET_NUM_MOUSE_CLICKS(string[3], gpm_event.clicks + 1);
	    break;
	case GPM_UP:
	    string[3] = MOUSE_RELEASE;
	    old_buttons &= ~gpm_event.buttons;
	    break;
	default:
	    return 0;
    }
    /*This code is based on gui_x11_mouse_cb in gui_x11.c */
    gpm_modifiers = gpm_event.modifiers;
    vim_modifiers = 0x0;
    /* I ignore capslock stats. Aren't we all just hate capslock mixing with
     * Vim commands ? Besides, gpm_event.modifiers is unsigned char, and
     * K_CAPSSHIFT is defined 8, so it probably isn't even reported
     */
    if (gpm_modifiers & ((1 << KG_SHIFT) | (1 << KG_SHIFTR) | (1 << KG_SHIFTL)))
	vim_modifiers |= MOUSE_SHIFT;

    if (gpm_modifiers & ((1 << KG_CTRL) | (1 << KG_CTRLR) | (1 << KG_CTRLL)))
	vim_modifiers |= MOUSE_CTRL;
    if (gpm_modifiers & ((1 << KG_ALT) | (1 << KG_ALTGR)))
	vim_modifiers |= MOUSE_ALT;
    string[3] |= vim_modifiers;
    string[4] = (char_u)(col + ' ' + 1);
    string[5] = (char_u)(row + ' ' + 1);
    add_to_input_buf(string, 6);
    return 6;
}
#endif /* FEAT_MOUSE_GPM */

#ifdef FEAT_SYSMOUSE
/*
 * Initialize connection with sysmouse.
 * Let virtual console inform us with SIGUSR2 for pending sysmouse
 * output, any sysmouse output than will be processed via sig_sysmouse().
 * Return OK if succeeded, FAIL if failed.
 */
    static int
sysmouse_open(void)
{
    struct mouse_info   mouse;

    mouse.operation = MOUSE_MODE;
    mouse.u.mode.mode = 0;
    mouse.u.mode.signal = SIGUSR2;
    if (ioctl(1, CONS_MOUSECTL, &mouse) != -1)
    {
	signal(SIGUSR2, (RETSIGTYPE (*)())sig_sysmouse);
	mouse.operation = MOUSE_SHOW;
	ioctl(1, CONS_MOUSECTL, &mouse);
	return OK;
    }
    return FAIL;
}

/*
 * Stop processing SIGUSR2 signals, and also make sure that
 * virtual console do not send us any sysmouse related signal.
 */
    static void
sysmouse_close(void)
{
    struct mouse_info	mouse;

    signal(SIGUSR2, restricted ? SIG_IGN : SIG_DFL);
    mouse.operation = MOUSE_MODE;
    mouse.u.mode.mode = 0;
    mouse.u.mode.signal = 0;
    ioctl(1, CONS_MOUSECTL, &mouse);
}

/*
 * Gets info from sysmouse and adds special keys to input buf.
 */
    static RETSIGTYPE
sig_sysmouse SIGDEFARG(sigarg)
{
    struct mouse_info	mouse;
    struct video_info	video;
    char_u		string[6];
    int			row, col;
    int			button;
    int			buttons;
    static int		oldbuttons = 0;

#ifdef FEAT_GUI
    /* Don't put events in the input queue now. */
    if (hold_gui_events)
	return;
#endif

    mouse.operation = MOUSE_GETINFO;
    if (ioctl(1, FBIO_GETMODE, &video.vi_mode) != -1
	    && ioctl(1, FBIO_MODEINFO, &video) != -1
	    && ioctl(1, CONS_MOUSECTL, &mouse) != -1
	    && video.vi_cheight > 0 && video.vi_cwidth > 0)
    {
	row = mouse.u.data.y / video.vi_cheight;
	col = mouse.u.data.x / video.vi_cwidth;
	buttons = mouse.u.data.buttons;
	string[0] = ESC; /* Our termcode */
	string[1] = 'M';
	string[2] = 'S';
	if (oldbuttons == buttons && buttons != 0)
	{
	    button = MOUSE_DRAG;
	}
	else
	{
	    switch (buttons)
	    {
		case 0:
		    button = MOUSE_RELEASE;
		    break;
		case 1:
		    button = MOUSE_LEFT;
		    break;
		case 2:
		    button = MOUSE_MIDDLE;
		    break;
		case 4:
		    button = MOUSE_RIGHT;
		    break;
		default:
		    return;
	    }
	    oldbuttons = buttons;
	}
	string[3] = (char_u)(button);
	string[4] = (char_u)(col + ' ' + 1);
	string[5] = (char_u)(row + ' ' + 1);
	add_to_input_buf(string, 6);
    }
    return;
}
#endif /* FEAT_SYSMOUSE */

#if defined(FEAT_LIBCALL) || defined(PROTO)
typedef char_u * (*STRPROCSTR)(char_u *);
typedef char_u * (*INTPROCSTR)(int);
typedef int (*STRPROCINT)(char_u *);
typedef int (*INTPROCINT)(int);

/*
 * Call a DLL routine which takes either a string or int param
 * and returns an allocated string.
 */
    int
mch_libcall(
    char_u	*libname,
    char_u	*funcname,
    char_u	*argstring,	/* NULL when using a argint */
    int		argint,
    char_u	**string_result,/* NULL when using number_result */
    int		*number_result)
{
# if defined(USE_DLOPEN)
    void	*hinstLib;
    char	*dlerr = NULL;
# else
    shl_t	hinstLib;
# endif
    STRPROCSTR	ProcAdd;
    INTPROCSTR	ProcAddI;
    char_u	*retval_str = NULL;
    int		retval_int = 0;
    int		success = FALSE;

    /*
     * Get a handle to the DLL module.
     */
# if defined(USE_DLOPEN)
    /* First clear any error, it's not cleared by the dlopen() call. */
    (void)dlerror();

    hinstLib = dlopen((char *)libname, RTLD_LAZY
#  ifdef RTLD_LOCAL
	    | RTLD_LOCAL
#  endif
	    );
    if (hinstLib == NULL)
    {
	/* "dlerr" must be used before dlclose() */
	dlerr = (char *)dlerror();
	if (dlerr != NULL)
	    semsg(_("dlerror = \"%s\""), dlerr);
    }
# else
    hinstLib = shl_load((const char*)libname, BIND_IMMEDIATE|BIND_VERBOSE, 0L);
# endif

    /* If the handle is valid, try to get the function address. */
    if (hinstLib != NULL)
    {
# ifdef HAVE_SETJMP_H
	/*
	 * Catch a crash when calling the library function.  For example when
	 * using a number where a string pointer is expected.
	 */
	mch_startjmp();
	if (SETJMP(lc_jump_env) != 0)
	{
	    success = FALSE;
#  if defined(USE_DLOPEN)
	    dlerr = NULL;
#  endif
	    mch_didjmp();
	}
	else
# endif
	{
	    retval_str = NULL;
	    retval_int = 0;

	    if (argstring != NULL)
	    {
# if defined(USE_DLOPEN)
		*(void **)(&ProcAdd) = dlsym(hinstLib, (const char *)funcname);
		dlerr = (char *)dlerror();
# else
		if (shl_findsym(&hinstLib, (const char *)funcname,
					TYPE_PROCEDURE, (void *)&ProcAdd) < 0)
		    ProcAdd = NULL;
# endif
		if ((success = (ProcAdd != NULL
# if defined(USE_DLOPEN)
			    && dlerr == NULL
# endif
			    )))
		{
		    if (string_result == NULL)
			retval_int = ((STRPROCINT)ProcAdd)(argstring);
		    else
			retval_str = (ProcAdd)(argstring);
		}
	    }
	    else
	    {
# if defined(USE_DLOPEN)
		*(void **)(&ProcAddI) = dlsym(hinstLib, (const char *)funcname);
		dlerr = (char *)dlerror();
# else
		if (shl_findsym(&hinstLib, (const char *)funcname,
				       TYPE_PROCEDURE, (void *)&ProcAddI) < 0)
		    ProcAddI = NULL;
# endif
		if ((success = (ProcAddI != NULL
# if defined(USE_DLOPEN)
			    && dlerr == NULL
# endif
			    )))
		{
		    if (string_result == NULL)
			retval_int = ((INTPROCINT)ProcAddI)(argint);
		    else
			retval_str = (ProcAddI)(argint);
		}
	    }

	    /* Save the string before we free the library. */
	    /* Assume that a "1" or "-1" result is an illegal pointer. */
	    if (string_result == NULL)
		*number_result = retval_int;
	    else if (retval_str != NULL
		    && retval_str != (char_u *)1
		    && retval_str != (char_u *)-1)
		*string_result = vim_strsave(retval_str);
	}

# ifdef HAVE_SETJMP_H
	mch_endjmp();
#  ifdef SIGHASARG
	if (lc_signal != 0)
	{
	    int i;

	    /* try to find the name of this signal */
	    for (i = 0; signal_info[i].sig != -1; i++)
		if (lc_signal == signal_info[i].sig)
		    break;
	    semsg("E368: got SIG%s in libcall()", signal_info[i].name);
	}
#  endif
# endif

# if defined(USE_DLOPEN)
	/* "dlerr" must be used before dlclose() */
	if (dlerr != NULL)
	    semsg(_("dlerror = \"%s\""), dlerr);

	/* Free the DLL module. */
	(void)dlclose(hinstLib);
# else
	(void)shl_unload(hinstLib);
# endif
    }

    if (!success)
    {
	semsg(_(e_libcall), funcname);
	return FAIL;
    }

    return OK;
}
#endif

#if (defined(FEAT_X11) && defined(FEAT_XCLIPBOARD)) || defined(PROTO)
static int	xterm_trace = -1;	/* default: disabled */
static int	xterm_button;

/*
 * Setup a dummy window for X selections in a terminal.
 */
    void
setup_term_clip(void)
{
    int		z = 0;
    char	*strp = "";
    Widget	AppShell;

    if (!x_connect_to_server())
	return;

    open_app_context();
    if (app_context != NULL && xterm_Shell == (Widget)0)
    {
	int (*oldhandler)();
#if defined(HAVE_SETJMP_H)
	int (*oldIOhandler)();
#endif
# ifdef ELAPSED_FUNC
	elapsed_T start_tv;

	if (p_verbose > 0)
	    ELAPSED_INIT(start_tv);
# endif

	/* Ignore X errors while opening the display */
	oldhandler = XSetErrorHandler(x_error_check);

#if defined(HAVE_SETJMP_H)
	/* Ignore X IO errors while opening the display */
	oldIOhandler = XSetIOErrorHandler(x_IOerror_check);
	mch_startjmp();
	if (SETJMP(lc_jump_env) != 0)
	{
	    mch_didjmp();
	    xterm_dpy = NULL;
	}
	else
#endif
	{
	    xterm_dpy = XtOpenDisplay(app_context, xterm_display,
		    "vim_xterm", "Vim_xterm", NULL, 0, &z, &strp);
	    if (xterm_dpy != NULL)
		xterm_dpy_retry_count = 0;
#if defined(HAVE_SETJMP_H)
	    mch_endjmp();
#endif
	}

#if defined(HAVE_SETJMP_H)
	/* Now handle X IO errors normally. */
	(void)XSetIOErrorHandler(oldIOhandler);
#endif
	/* Now handle X errors normally. */
	(void)XSetErrorHandler(oldhandler);

	if (xterm_dpy == NULL)
	{
	    if (p_verbose > 0)
		verb_msg(_("Opening the X display failed"));
	    return;
	}

	/* Catch terminating error of the X server connection. */
	(void)XSetIOErrorHandler(x_IOerror_handler);

# ifdef ELAPSED_FUNC
	if (p_verbose > 0)
	{
	    verbose_enter();
	    xopen_message(ELAPSED_FUNC(start_tv));
	    verbose_leave();
	}
# endif

	/* Create a Shell to make converters work. */
	AppShell = XtVaAppCreateShell("vim_xterm", "Vim_xterm",
		applicationShellWidgetClass, xterm_dpy,
		NULL);
	if (AppShell == (Widget)0)
	    return;
	xterm_Shell = XtVaCreatePopupShell("VIM",
		topLevelShellWidgetClass, AppShell,
		XtNmappedWhenManaged, 0,
		XtNwidth, 1,
		XtNheight, 1,
		NULL);
	if (xterm_Shell == (Widget)0)
	    return;

	x11_setup_atoms(xterm_dpy);
	x11_setup_selection(xterm_Shell);
	if (x11_display == NULL)
	    x11_display = xterm_dpy;

	XtRealizeWidget(xterm_Shell);
	XSync(xterm_dpy, False);
	xterm_update();
    }
    if (xterm_Shell != (Widget)0)
    {
	clip_init(TRUE);
	if (x11_window == 0 && (strp = getenv("WINDOWID")) != NULL)
	    x11_window = (Window)atol(strp);
	/* Check if $WINDOWID is valid. */
	if (test_x11_window(xterm_dpy) == FAIL)
	    x11_window = 0;
	if (x11_window != 0)
	    xterm_trace = 0;
    }
}

    void
start_xterm_trace(int button)
{
    if (x11_window == 0 || xterm_trace < 0 || xterm_Shell == (Widget)0)
	return;
    xterm_trace = 1;
    xterm_button = button;
    do_xterm_trace();
}


    void
stop_xterm_trace(void)
{
    if (xterm_trace < 0)
	return;
    xterm_trace = 0;
}

/*
 * Query the xterm pointer and generate mouse termcodes if necessary
 * return TRUE if dragging is active, else FALSE
 */
    static int
do_xterm_trace(void)
{
    Window		root, child;
    int			root_x, root_y;
    int			win_x, win_y;
    int			row, col;
    int_u		mask_return;
    char_u		buf[50];
    char_u		*strp;
    long		got_hints;
    static char_u	*mouse_code;
    static char_u	mouse_name[2] = {KS_MOUSE, KE_FILLER};
    static int		prev_row = 0, prev_col = 0;
    static XSizeHints	xterm_hints;

    if (xterm_trace <= 0)
	return FALSE;

    if (xterm_trace == 1)
    {
	/* Get the hints just before tracking starts.  The font size might
	 * have changed recently. */
	if (!XGetWMNormalHints(xterm_dpy, x11_window, &xterm_hints, &got_hints)
		|| !(got_hints & PResizeInc)
		|| xterm_hints.width_inc <= 1
		|| xterm_hints.height_inc <= 1)
	{
	    xterm_trace = -1;  /* Not enough data -- disable tracing */
	    return FALSE;
	}

	/* Rely on the same mouse code for the duration of this */
	mouse_code = find_termcode(mouse_name);
	prev_row = mouse_row;
	prev_col = mouse_col;
	xterm_trace = 2;

	/* Find the offset of the chars, there might be a scrollbar on the
	 * left of the window and/or a menu on the top (eterm etc.) */
	XQueryPointer(xterm_dpy, x11_window, &root, &child, &root_x, &root_y,
		      &win_x, &win_y, &mask_return);
	xterm_hints.y = win_y - (xterm_hints.height_inc * mouse_row)
			      - (xterm_hints.height_inc / 2);
	if (xterm_hints.y <= xterm_hints.height_inc / 2)
	    xterm_hints.y = 2;
	xterm_hints.x = win_x - (xterm_hints.width_inc * mouse_col)
			      - (xterm_hints.width_inc / 2);
	if (xterm_hints.x <= xterm_hints.width_inc / 2)
	    xterm_hints.x = 2;
	return TRUE;
    }
    if (mouse_code == NULL || STRLEN(mouse_code) > 45)
    {
	xterm_trace = 0;
	return FALSE;
    }

    XQueryPointer(xterm_dpy, x11_window, &root, &child, &root_x, &root_y,
		  &win_x, &win_y, &mask_return);

    row = check_row((win_y - xterm_hints.y) / xterm_hints.height_inc);
    col = check_col((win_x - xterm_hints.x) / xterm_hints.width_inc);
    if (row == prev_row && col == prev_col)
	return TRUE;

    STRCPY(buf, mouse_code);
    strp = buf + STRLEN(buf);
    *strp++ = (xterm_button | MOUSE_DRAG) & ~0x20;
    *strp++ = (char_u)(col + ' ' + 1);
    *strp++ = (char_u)(row + ' ' + 1);
    *strp = 0;
    add_to_input_buf(buf, STRLEN(buf));

    prev_row = row;
    prev_col = col;
    return TRUE;
}

# if defined(FEAT_GUI) || defined(PROTO)
/*
 * Destroy the display, window and app_context.  Required for GTK.
 */
    void
clear_xterm_clip(void)
{
    if (xterm_Shell != (Widget)0)
    {
	XtDestroyWidget(xterm_Shell);
	xterm_Shell = (Widget)0;
    }
    if (xterm_dpy != NULL)
    {
#  if 0
	/* Lesstif and Solaris crash here, lose some memory */
	XtCloseDisplay(xterm_dpy);
#  endif
	if (x11_display == xterm_dpy)
	    x11_display = NULL;
	xterm_dpy = NULL;
    }
#  if 0
    if (app_context != (XtAppContext)NULL)
    {
	/* Lesstif and Solaris crash here, lose some memory */
	XtDestroyApplicationContext(app_context);
	app_context = (XtAppContext)NULL;
    }
#  endif
}
# endif

/*
 * Catch up with GUI or X events.
 */
    static void
clip_update(void)
{
# ifdef FEAT_GUI
    if (gui.in_use)
	gui_mch_update();
    else
# endif
    if (xterm_Shell != (Widget)0)
	xterm_update();
}

/*
 * Catch up with any queued X events.  This may put keyboard input into the
 * input buffer, call resize call-backs, trigger timers etc.  If there is
 * nothing in the X event queue (& no timers pending), then we return
 * immediately.
 */
    static void
xterm_update(void)
{
    XEvent event;

    for (;;)
    {
	XtInputMask mask = XtAppPending(app_context);

	if (mask == 0 || vim_is_input_buf_full())
	    break;

	if (mask & XtIMXEvent)
	{
	    /* There is an event to process. */
	    XtAppNextEvent(app_context, &event);
#ifdef FEAT_CLIENTSERVER
	    {
		XPropertyEvent *e = (XPropertyEvent *)&event;

		if (e->type == PropertyNotify && e->window == commWindow
		   && e->atom == commProperty && e->state == PropertyNewValue)
		    serverEventProc(xterm_dpy, &event, 0);
	    }
#endif
	    XtDispatchEvent(&event);
	}
	else
	{
	    /* There is something else than an event to process. */
	    XtAppProcessEvent(app_context, mask);
	}
    }
}

    int
clip_xterm_own_selection(VimClipboard *cbd)
{
    if (xterm_Shell != (Widget)0)
	return clip_x11_own_selection(xterm_Shell, cbd);
    return FAIL;
}

    void
clip_xterm_lose_selection(VimClipboard *cbd)
{
    if (xterm_Shell != (Widget)0)
	clip_x11_lose_selection(xterm_Shell, cbd);
}

    void
clip_xterm_request_selection(VimClipboard *cbd)
{
    if (xterm_Shell != (Widget)0)
	clip_x11_request_selection(xterm_Shell, xterm_dpy, cbd);
}

    void
clip_xterm_set_selection(VimClipboard *cbd)
{
    clip_x11_set_selection(cbd);
}
#endif


#if defined(USE_XSMP) || defined(PROTO)
/*
 * Code for X Session Management Protocol.
 */

# if defined(FEAT_GUI) && defined(USE_XSMP_INTERACT)
/*
 * This is our chance to ask the user if they want to save,
 * or abort the logout
 */
    static void
xsmp_handle_interaction(SmcConn smc_conn, SmPointer client_data UNUSED)
{
    cmdmod_T	save_cmdmod;
    int		cancel_shutdown = False;

    save_cmdmod = cmdmod;
    cmdmod.confirm = TRUE;
    if (check_changed_any(FALSE, FALSE))
	/* Mustn't logout */
	cancel_shutdown = True;
    cmdmod = save_cmdmod;
    setcursor();		/* position cursor */
    out_flush();

    /* Done interaction */
    SmcInteractDone(smc_conn, cancel_shutdown);

    /* Finish off
     * Only end save-yourself here if we're not cancelling shutdown;
     * we'll get a cancelled callback later in which we'll end it.
     * Hopefully get around glitchy SMs (like GNOME-1)
     */
    if (!cancel_shutdown)
    {
	xsmp.save_yourself = False;
	SmcSaveYourselfDone(smc_conn, True);
    }
}
# endif

/*
 * Callback that starts save-yourself.
 */
    static void
xsmp_handle_save_yourself(
    SmcConn	smc_conn,
    SmPointer	client_data UNUSED,
    int		save_type UNUSED,
    Bool	shutdown,
    int		interact_style UNUSED,
    Bool	fast UNUSED)
{
    /* Handle already being in saveyourself */
    if (xsmp.save_yourself)
	SmcSaveYourselfDone(smc_conn, True);
    xsmp.save_yourself = True;
    xsmp.shutdown = shutdown;

    /* First up, preserve all files */
    out_flush();
    ml_sync_all(FALSE, FALSE);	/* preserve all swap files */

    if (p_verbose > 0)
	verb_msg(_("XSMP handling save-yourself request"));

# if defined(FEAT_GUI) && defined(USE_XSMP_INTERACT)
    /* Now see if we can ask about unsaved files */
    if (shutdown && !fast && gui.in_use)
	/* Need to interact with user, but need SM's permission */
	SmcInteractRequest(smc_conn, SmDialogError,
					xsmp_handle_interaction, client_data);
    else
# endif
    {
	/* Can stop the cycle here */
	SmcSaveYourselfDone(smc_conn, True);
	xsmp.save_yourself = False;
    }
}


/*
 * Callback to warn us of imminent death.
 */
    static void
xsmp_die(SmcConn smc_conn UNUSED, SmPointer client_data UNUSED)
{
    xsmp_close();

    /* quit quickly leaving swapfiles for modified buffers behind */
    getout_preserve_modified(0);
}


/*
 * Callback to tell us that save-yourself has completed.
 */
    static void
xsmp_save_complete(
    SmcConn	smc_conn UNUSED,
    SmPointer	client_data UNUSED)
{
    xsmp.save_yourself = False;
}


/*
 * Callback to tell us that an instigated shutdown was cancelled
 * (maybe even by us)
 */
    static void
xsmp_shutdown_cancelled(
    SmcConn	smc_conn,
    SmPointer	client_data UNUSED)
{
    if (xsmp.save_yourself)
	SmcSaveYourselfDone(smc_conn, True);
    xsmp.save_yourself = False;
    xsmp.shutdown = False;
}


/*
 * Callback to tell us that a new ICE connection has been established.
 */
    static void
xsmp_ice_connection(
    IceConn	iceConn,
    IcePointer	clientData UNUSED,
    Bool	opening,
    IcePointer	*watchData UNUSED)
{
    /* Intercept creation of ICE connection fd */
    if (opening)
    {
	xsmp_icefd = IceConnectionNumber(iceConn);
	IceRemoveConnectionWatch(xsmp_ice_connection, NULL);
    }
}


/* Handle any ICE processing that's required; return FAIL if SM lost */
    int
xsmp_handle_requests(void)
{
    Bool rep;

    if (IceProcessMessages(xsmp.iceconn, NULL, &rep)
						 == IceProcessMessagesIOError)
    {
	/* Lost ICE */
	if (p_verbose > 0)
	    verb_msg(_("XSMP lost ICE connection"));
	xsmp_close();
	return FAIL;
    }
    else
	return OK;
}

static int dummy;

/* Set up X Session Management Protocol */
    void
xsmp_init(void)
{
    char		errorstring[80];
    SmcCallbacks	smcallbacks;
#if 0
    SmPropValue		smname;
    SmProp		smnameprop;
    SmProp		*smprops[1];
#endif

    if (p_verbose > 0)
	verb_msg(_("XSMP opening connection"));

    xsmp.save_yourself = xsmp.shutdown = False;

    /* Set up SM callbacks - must have all, even if they're not used */
    smcallbacks.save_yourself.callback = xsmp_handle_save_yourself;
    smcallbacks.save_yourself.client_data = NULL;
    smcallbacks.die.callback = xsmp_die;
    smcallbacks.die.client_data = NULL;
    smcallbacks.save_complete.callback = xsmp_save_complete;
    smcallbacks.save_complete.client_data = NULL;
    smcallbacks.shutdown_cancelled.callback = xsmp_shutdown_cancelled;
    smcallbacks.shutdown_cancelled.client_data = NULL;

    /* Set up a watch on ICE connection creations.  The "dummy" argument is
     * apparently required for FreeBSD (we get a BUS error when using NULL). */
    if (IceAddConnectionWatch(xsmp_ice_connection, &dummy) == 0)
    {
	if (p_verbose > 0)
	    verb_msg(_("XSMP ICE connection watch failed"));
	return;
    }

    /* Create an SM connection */
    xsmp.smcconn = SmcOpenConnection(
	    NULL,
	    NULL,
	    SmProtoMajor,
	    SmProtoMinor,
	    SmcSaveYourselfProcMask | SmcDieProcMask
		     | SmcSaveCompleteProcMask | SmcShutdownCancelledProcMask,
	    &smcallbacks,
	    NULL,
	    &xsmp.clientid,
	    sizeof(errorstring) - 1,
	    errorstring);
    if (xsmp.smcconn == NULL)
    {
	char errorreport[132];

	if (p_verbose > 0)
	{
	    vim_snprintf(errorreport, sizeof(errorreport),
			 _("XSMP SmcOpenConnection failed: %s"), errorstring);
	    verb_msg(errorreport);
	}
	return;
    }
    xsmp.iceconn = SmcGetIceConnection(xsmp.smcconn);

#if 0
    /* ID ourselves */
    smname.value = "vim";
    smname.length = 3;
    smnameprop.name = "SmProgram";
    smnameprop.type = "SmARRAY8";
    smnameprop.num_vals = 1;
    smnameprop.vals = &smname;

    smprops[0] = &smnameprop;
    SmcSetProperties(xsmp.smcconn, 1, smprops);
#endif
}


/* Shut down XSMP comms. */
    void
xsmp_close(void)
{
    if (xsmp_icefd != -1)
    {
	SmcCloseConnection(xsmp.smcconn, 0, NULL);
	if (xsmp.clientid != NULL)
	    free(xsmp.clientid);
	xsmp.clientid = NULL;
	xsmp_icefd = -1;
    }
}
#endif /* USE_XSMP */


#ifdef EBCDIC
/* Translate character to its CTRL- value */
char CtrlTable[] =
{
/* 00 - 5E */
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* ^ */ 0x1E,
/* - */ 0x1F,
/* 61 - 6C */
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* _ */ 0x1F,
/* 6E - 80 */
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* a */ 0x01,
/* b */ 0x02,
/* c */ 0x03,
/* d */ 0x37,
/* e */ 0x2D,
/* f */ 0x2E,
/* g */ 0x2F,
/* h */ 0x16,
/* i */ 0x05,
/* 8A - 90 */
	0, 0, 0, 0, 0, 0, 0,
/* j */ 0x15,
/* k */ 0x0B,
/* l */ 0x0C,
/* m */ 0x0D,
/* n */ 0x0E,
/* o */ 0x0F,
/* p */ 0x10,
/* q */ 0x11,
/* r */ 0x12,
/* 9A - A1 */
	0, 0, 0, 0, 0, 0, 0, 0,
/* s */ 0x13,
/* t */ 0x3C,
/* u */ 0x3D,
/* v */ 0x32,
/* w */ 0x26,
/* x */ 0x18,
/* y */ 0x19,
/* z */ 0x3F,
/* AA - AC */
	0, 0, 0,
/* [ */ 0x27,
/* AE - BC */
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* ] */ 0x1D,
/* BE - C0 */ 0, 0, 0,
/* A */ 0x01,
/* B */ 0x02,
/* C */ 0x03,
/* D */ 0x37,
/* E */ 0x2D,
/* F */ 0x2E,
/* G */ 0x2F,
/* H */ 0x16,
/* I */ 0x05,
/* CA - D0 */ 0, 0, 0, 0, 0, 0, 0,
/* J */ 0x15,
/* K */ 0x0B,
/* L */ 0x0C,
/* M */ 0x0D,
/* N */ 0x0E,
/* O */ 0x0F,
/* P */ 0x10,
/* Q */ 0x11,
/* R */ 0x12,
/* DA - DF */ 0, 0, 0, 0, 0, 0,
/* \ */ 0x1C,
/* E1 */ 0,
/* S */ 0x13,
/* T */ 0x3C,
/* U */ 0x3D,
/* V */ 0x32,
/* W */ 0x26,
/* X */ 0x18,
/* Y */ 0x19,
/* Z */ 0x3F,
/* EA - FF*/ 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
};

char MetaCharTable[]=
{/*   0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F */
      0,  0,  0,  0,'\\', 0,'F',  0,'W','M','N',  0,  0,  0,  0,  0,
      0,  0,  0,  0,']',  0,  0,'G',  0,  0,'R','O',  0,  0,  0,  0,
    '@','A','B','C','D','E',  0,  0,'H','I','J','K','L',  0,  0,  0,
    'P','Q',  0,'S','T','U','V',  0,'X','Y','Z','[',  0,  0,'^',  0
};


/* TODO: Use characters NOT numbers!!! */
char CtrlCharTable[]=
{/*   0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F */
    124,193,194,195,  0,201,  0,  0,  0,  0,  0,210,211,212,213,214,
    215,216,217,226,  0,209,200,  0,231,232,  0,  0,224,189, 95,109,
      0,  0,  0,  0,  0,  0,230,173,  0,  0,  0,  0,  0,197,198,199,
      0,  0,229,  0,  0,  0,  0,196,  0,  0,  0,  0,227,228,  0,233,
};


#endif