diff --git a/test/ditto.c b/test/ditto.c
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+/****************************************************************************
+ * Copyright (c) 1998-2011,2012 Free Software Foundation, Inc.              *
+ *                                                                          *
+ * Permission is hereby granted, free of charge, to any person obtaining a  *
+ * copy of this software and associated documentation files (the            *
+ * "Software"), to deal in the Software without restriction, including      *
+ * without limitation the rights to use, copy, modify, merge, publish,      *
+ * distribute, distribute with modifications, sublicense, and/or sell       *
+ * copies of the Software, and to permit persons to whom the Software is    *
+ * furnished to do so, subject to the following conditions:                 *
+ *                                                                          *
+ * The above copyright notice and this permission notice shall be included  *
+ * in all copies or substantial portions of the Software.                   *
+ *                                                                          *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
+ * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
+ * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
+ *                                                                          *
+ * Except as contained in this notice, the name(s) of the above copyright   *
+ * holders shall not be used in advertising or otherwise to promote the     *
+ * sale, use or other dealings in this Software without prior written       *
+ * authorization.                                                           *
+ ****************************************************************************/
+
+/*
+ * Author: Thomas E. Dickey (1998-on)
+ *
+ * $Id: ditto.c,v 1.42 2012/11/24 20:16:18 tom Exp $
+ *
+ * The program illustrates how to set up multiple screens from a single
+ * program.
+ *
+ * If openpty() is supported, the command line parameters are titles for
+ * the windows showing each screen's data.
+ *
+ * If openpty() is not supported, you must invoke the program by specifying
+ * another terminal on the same machine by specifying its device, e.g.,
+ *	ditto /dev/ttyp1
+ */
+#include <test.priv.h>
+#include <sys/stat.h>
+
+#ifdef USE_PTHREADS
+#include <pthread.h>
+#endif
+
+#ifdef USE_XTERM_PTY
+#include USE_OPENPTY_HEADER
+#endif
+
+#define MAX_FIFO 256
+
+#define THIS_FIFO(n) ((n) % MAX_FIFO)
+#define NEXT_FIFO(n) THIS_FIFO((n) + 1)
+
+typedef struct {
+    unsigned long sequence;
+    int head;
+    int tail;
+    int data[MAX_FIFO];
+} FIFO;
+
+typedef struct {
+    unsigned long sequence;
+} PEEK;
+
+/*
+ * Data "owned" for a single screen.  Each screen is divided into windows that
+ * show the text read from each terminal.  Input from a given screen will also
+ * be read into one window per screen.
+ */
+typedef struct {
+    FILE *input;
+    FILE *output;
+    SCREEN *screen;		/* this screen - curses internal data */
+    int which1;			/* this screen's index in DITTO[] array */
+    int length;			/* length of windows[] and peeks[] */
+    char **titles;		/* per-window titles */
+    WINDOW **parents;		/* display boxes around each screen's data */
+    WINDOW **windows;		/* display data from each screen */
+    PEEK *peeks;		/* indices for each screen's fifo */
+    FIFO fifo;			/* fifo for this screen */
+#ifdef USE_PTHREADS
+    pthread_t thread;
+#endif
+} DITTO;
+
+/*
+ * Structure used to pass multiple parameters via the use_screen()
+ * single-parameter interface.
+ */
+typedef struct {
+    int source;			/* which screen did character come from */
+    int target;			/* which screen is character going to */
+    DITTO *ditto;		/* data for all screens */
+} DDATA;
+
+static void failed(const char *) GCC_NORETURN;
+static void usage(void) GCC_NORETURN;
+
+static void
+failed(const char *s)
+{
+    perror(s);
+    ExitProgram(EXIT_FAILURE);
+}
+
+static void
+usage(void)
+{
+    fprintf(stderr, "usage: ditto [terminal1 ...]\n");
+    ExitProgram(EXIT_FAILURE);
+}
+
+/* Add to the head of the fifo, checking for overflow. */
+static void
+put_fifo(FIFO * fifo, int value)
+{
+    int next = NEXT_FIFO(fifo->head);
+    if (next == fifo->tail)
+	fifo->tail = NEXT_FIFO(fifo->tail);
+    fifo->data[next] = value;
+    fifo->head = next;
+    fifo->sequence += 1;
+}
+
+/* Get data from the tail (oldest part) of the fifo, returning -1 if no data.
+ * Since each screen can peek into the fifo, we do not update the tail index,
+ * but modify the peek-index.
+ *
+ * FIXME - test/workaround for case where fifo gets more than a buffer
+ * ahead of peek.
+ */
+static int
+peek_fifo(FIFO * fifo, PEEK * peek)
+{
+    int result = -1;
+    if (peek->sequence < fifo->sequence) {
+	result = fifo->data[THIS_FIFO(peek->sequence)];
+	peek->sequence += 1;
+    }
+    return result;
+}
+
+static FILE *
+open_tty(char *path)
+{
+    FILE *fp;
+#ifdef USE_XTERM_PTY
+    int amaster;
+    int aslave;
+    char slave_name[1024];
+    char s_option[sizeof(slave_name) + 80];
+
+    if (openpty(&amaster, &aslave, slave_name, 0, 0) != 0
+	|| strlen(slave_name) > sizeof(slave_name) - 1)
+	failed("openpty");
+    if (strrchr(slave_name, '/') == 0) {
+	errno = EISDIR;
+	failed(slave_name);
+    }
+    sprintf(s_option, "-S%s/%d", slave_name, aslave);
+    if (fork()) {
+	execlp("xterm", "xterm", s_option, "-title", path, (char *) 0);
+	_exit(0);
+    }
+    fp = fdopen(amaster, "r+");
+    if (fp == 0)
+	failed(path);
+#else
+    struct stat sb;
+
+    if (stat(path, &sb) < 0)
+	failed(path);
+    if ((sb.st_mode & S_IFMT) != S_IFCHR) {
+	errno = ENOTTY;
+	failed(path);
+    }
+    fp = fopen(path, "r+");
+    if (fp == 0)
+	failed(path);
+    printf("opened %s\n", path);
+#endif
+    assert(fp != 0);
+    return fp;
+}
+
+static void
+init_screen(
+#if HAVE_USE_WINDOW
+	       SCREEN *sp GCC_UNUSED,
+#endif
+	       void *arg)
+{
+    DITTO *target = (DITTO *) arg;
+    int high, wide;
+    int k;
+
+    cbreak();
+    noecho();
+    scrollok(stdscr, TRUE);
+    box(stdscr, 0, 0);
+
+    target->parents = typeCalloc(WINDOW *, (size_t) target->length);
+    target->windows = typeCalloc(WINDOW *, (size_t) target->length);
+    target->peeks = typeCalloc(PEEK, (size_t) target->length);
+
+    high = (LINES - 2) / target->length;
+    wide = (COLS - 2);
+    for (k = 0; k < target->length; ++k) {
+	WINDOW *outer = newwin(high, wide, 1 + (high * k), 1);
+	WINDOW *inner = derwin(outer, high - 2, wide - 2, 1, 1);
+
+	box(outer, 0, 0);
+	MvWAddStr(outer, 0, 2, target->titles[k]);
+	wnoutrefresh(outer);
+
+	scrollok(inner, TRUE);
+	keypad(inner, TRUE);
+#ifndef USE_PTHREADS
+	nodelay(inner, TRUE);
+#endif
+
+	target->parents[k] = outer;
+	target->windows[k] = inner;
+    }
+    doupdate();
+}
+
+static void
+open_screen(DITTO * target, char **source, int length, int which1)
+{
+    if (which1 != 0) {
+	target->input =
+	    target->output = open_tty(source[which1]);
+    } else {
+	target->input = stdin;
+	target->output = stdout;
+    }
+
+    target->which1 = which1;
+    target->titles = source;
+    target->length = length;
+    target->fifo.head = -1;
+    target->screen = newterm((char *) 0,	/* assume $TERM is the same */
+			     target->output,
+			     target->input);
+
+    if (target->screen == 0)
+	failed("newterm");
+
+    (void) USING_SCREEN(target->screen, init_screen, target);
+}
+
+static int
+close_screen(
+#if HAVE_USE_WINDOW
+		SCREEN *sp GCC_UNUSED,
+#endif
+		void *arg GCC_UNUSED)
+{
+#if HAVE_USE_WINDOW
+    (void) sp;
+#endif
+    (void) arg;
+    return endwin();
+}
+
+/*
+ * Read data from the 'source' screen.
+ */
+static int
+read_screen(
+#if HAVE_USE_WINDOW
+	       SCREEN *sp GCC_UNUSED,
+#endif
+	       void *arg)
+{
+    DDATA *data = (DDATA *) arg;
+    DITTO *ditto = &(data->ditto[data->source]);
+    WINDOW *win = ditto->windows[data->source];
+    int ch = wgetch(win);
+
+    if (ch > 0 && ch < 256)
+	put_fifo(&(ditto->fifo), ch);
+    else
+	ch = ERR;
+
+    return ch;
+}
+
+/*
+ * Write all of the data that's in fifos for the 'target' screen.
+ */
+static int
+write_screen(
+#if HAVE_USE_WINDOW
+		SCREEN *sp GCC_UNUSED,
+#endif
+		void *arg GCC_UNUSED)
+{
+    DDATA *data = (DDATA *) arg;
+    DITTO *ditto = &(data->ditto[data->target]);
+    bool changed = FALSE;
+    int which;
+
+    for (which = 0; which < ditto->length; ++which) {
+	WINDOW *win = ditto->windows[which];
+	FIFO *fifo = &(data->ditto[which].fifo);
+	PEEK *peek = &(ditto->peeks[which]);
+	int ch;
+
+	while ((ch = peek_fifo(fifo, peek)) > 0) {
+	    changed = TRUE;
+
+	    waddch(win, (chtype) ch);
+	    wnoutrefresh(win);
+	}
+    }
+
+    if (changed)
+	doupdate();
+    return OK;
+}
+
+static void
+show_ditto(DITTO * data, int count, DDATA * ddata)
+{
+    int n;
+
+    (void) data;
+    for (n = 0; n < count; n++) {
+	ddata->target = n;
+	USING_SCREEN(data[n].screen, write_screen, (void *) ddata);
+    }
+}
+
+#ifdef USE_PTHREADS
+static void *
+handle_screen(void *arg)
+{
+    DDATA ddata;
+    int ch;
+
+    memset(&ddata, 0, sizeof(ddata));
+    ddata.ditto = (DITTO *) arg;
+    ddata.source = ddata.ditto->which1;
+    ddata.ditto -= ddata.source;	/* -> base of array */
+
+    for (;;) {
+	ch = read_screen(ddata.ditto->screen, &ddata);
+	if (ch == CTRL('D')) {
+	    int later = (ddata.source ? ddata.source : -1);
+	    int j;
+
+	    for (j = ddata.ditto->length - 1; j > 0; --j) {
+		if (j != later) {
+		    pthread_cancel(ddata.ditto[j].thread);
+		}
+	    }
+	    if (later > 0) {
+		pthread_cancel(ddata.ditto[later].thread);
+	    }
+	    break;
+	}
+	show_ditto(ddata.ditto, ddata.ditto->length, &ddata);
+    }
+    return NULL;
+}
+#endif
+
+int
+main(int argc, char *argv[])
+{
+    int j;
+    DITTO *data;
+#ifndef USE_PTHREADS
+    int count;
+#endif
+
+    if (argc <= 1)
+	usage();
+
+    if ((data = typeCalloc(DITTO, (size_t) argc)) == 0)
+	failed("calloc data");
+
+    assert(data != 0);
+
+    for (j = 0; j < argc; j++) {
+	open_screen(&data[j], argv, argc, j);
+    }
+
+#ifdef USE_PTHREADS
+    /*
+     * For multi-threaded operation, set up a reader for each of the screens.
+     * That uses blocking I/O rather than polling for input, so no calls to
+     * napms() are needed.
+     */
+    for (j = 0; j < argc; j++) {
+	(void) pthread_create(&(data[j].thread), NULL, handle_screen, &data[j]);
+    }
+    pthread_join(data[1].thread, NULL);
+#else
+    /*
+     * Loop, reading characters from any of the inputs and writing to all
+     * of the screens.
+     */
+    for (count = 0;; ++count) {
+	DDATA ddata;
+	int ch;
+	int which = (count % argc);
+
+	napms(20);
+
+	ddata.source = which;
+	ddata.ditto = data;
+
+	ch = USING_SCREEN(data[which].screen, read_screen, &ddata);
+	if (ch == CTRL('D')) {
+	    break;
+	} else if (ch != ERR) {
+	    show_ditto(data, argc, &ddata);
+	}
+    }
+#endif
+
+    /*
+     * Cleanup and exit
+     */
+    for (j = argc - 1; j >= 0; j--) {
+	USING_SCREEN(data[j].screen, close_screen, 0);
+	fprintf(data[j].output, "**Closed\r\n");
+
+	/*
+	 * Closing before a delscreen() helps ncurses determine that there
+	 * is no valid output buffer, and can remove the setbuf() data.
+	 */
+	fflush(data[j].output);
+	fclose(data[j].output);
+	delscreen(data[j].screen);
+    }
+    ExitProgram(EXIT_SUCCESS);
+}