diff --git a/src/if_tcl.c b/src/if_tcl.c
index 9fb5c34..3ef1544 100644
--- a/src/if_tcl.c
+++ b/src/if_tcl.c
@@ -237,8 +237,7 @@
 #endif
 
     void
-vim_tcl_init(arg)
-    char	*arg;
+vim_tcl_init(char *arg)
 {
 #ifndef DYNAMIC_TCL
     Tcl_FindExecutable(arg);
@@ -255,8 +254,7 @@
  * Return TRUE if the TCL interface can be used.
  */
     int
-tcl_enabled(verbose)
-    int		verbose;
+tcl_enabled(int verbose)
 {
     if (!stubs_initialized && find_executable_arg != NULL
 	    && tcl_runtime_link_init((char *)p_tcldll, verbose) == OK)
@@ -280,7 +278,7 @@
 #endif
 
     void
-tcl_end()
+tcl_end(void)
 {
 #ifdef DYNAMIC_TCL
     if (hTclLib)
@@ -310,11 +308,11 @@
  * useless for this routine to return the exit code via Tcl_SetResult().
  */
     static int
-exitcmd(dummy, interp, objc, objv)
-    ClientData dummy UNUSED;
-    Tcl_Interp *interp;
-    int objc;
-    Tcl_Obj *CONST objv[];
+exitcmd(
+    ClientData dummy UNUSED,
+    Tcl_Interp *interp,
+    int objc,
+    Tcl_Obj *CONST objv[])
 {
     int value = 0;
 
@@ -339,11 +337,11 @@
  *  "::vim::beep" - what Vi[m] does best :-)
  */
     static int
-beepcmd(dummy, interp, objc, objv)
-    ClientData dummy UNUSED;
-    Tcl_Interp *interp;
-    int objc;
-    Tcl_Obj *CONST objv[];
+beepcmd(
+    ClientData dummy UNUSED,
+    Tcl_Interp *interp,
+    int objc,
+    Tcl_Obj *CONST objv[])
 {
     if (objc != 1)
     {
@@ -361,11 +359,11 @@
  *  "::vim::buffer new" - create a new buffer (not implemented)
  */
     static int
-buffercmd(dummy, interp, objc, objv)
-    ClientData dummy UNUSED;
-    Tcl_Interp *interp;
-    int objc;
-    Tcl_Obj *CONST objv[];
+buffercmd(
+    ClientData dummy UNUSED,
+    Tcl_Interp *interp,
+    int objc,
+    Tcl_Obj *CONST objv[])
 {
     char	*name;
     buf_T	*buf;
@@ -457,11 +455,11 @@
  * "::vim::window list" - create list of window commands.
  */
     static int
-windowcmd(dummy, interp, objc, objv)
-    ClientData	dummy UNUSED;
-    Tcl_Interp	*interp;
-    int		objc;
-    Tcl_Obj	*CONST objv[];
+windowcmd(
+    ClientData	dummy UNUSED,
+    Tcl_Interp	*interp,
+    int		objc,
+    Tcl_Obj	*CONST objv[])
 {
     char	*what, *string;
     win_T	*win;
@@ -498,11 +496,11 @@
  * This function implements the buffer commands.
  */
     static int
-bufselfcmd(ref, interp, objc, objv)
-    ClientData	ref;
-    Tcl_Interp	*interp;
-    int		objc;
-    Tcl_Obj	*CONST objv[];
+bufselfcmd(
+    ClientData	ref,
+    Tcl_Interp	*interp,
+    int		objc,
+    Tcl_Obj	*CONST objv[])
 {
     int		opt, err, idx, flags;
     int		val1, val2, n, i;
@@ -937,11 +935,11 @@
  * This function implements the window commands.
  */
     static int
-winselfcmd(ref, interp, objc, objv)
-    ClientData	ref;
-    Tcl_Interp	*interp;
-    int		objc;
-    Tcl_Obj	*CONST objv[];
+winselfcmd(
+    ClientData	ref,
+    Tcl_Interp	*interp,
+    int		objc,
+    Tcl_Obj	*CONST objv[])
 {
     int		err, idx, flags;
     int		val1, val2;
@@ -1111,11 +1109,11 @@
 
 
     static int
-commandcmd(dummy, interp, objc, objv)
-    ClientData	dummy UNUSED;
-    Tcl_Interp	*interp;
-    int		objc;
-    Tcl_Obj	*CONST objv[];
+commandcmd(
+    ClientData	dummy UNUSED,
+    Tcl_Interp	*interp,
+    int		objc,
+    Tcl_Obj	*CONST objv[])
 {
     int		err;
 
@@ -1125,11 +1123,11 @@
 }
 
     static int
-optioncmd(dummy, interp, objc, objv)
-    ClientData	dummy UNUSED;
-    Tcl_Interp	*interp;
-    int		objc;
-    Tcl_Obj	*CONST objv[];
+optioncmd(
+    ClientData	dummy UNUSED,
+    Tcl_Interp	*interp,
+    int		objc,
+    Tcl_Obj	*CONST objv[])
 {
     int		err;
 
@@ -1139,11 +1137,11 @@
 }
 
     static int
-exprcmd(dummy, interp, objc, objv)
-    ClientData	dummy UNUSED;
-    Tcl_Interp	*interp;
-    int		objc;
-    Tcl_Obj	*CONST objv[];
+exprcmd(
+    ClientData	dummy UNUSED,
+    Tcl_Interp	*interp,
+    int		objc,
+    Tcl_Obj	*CONST objv[])
 {
     return tclvimexpr(interp, objc, objv, 1);
 }
@@ -1156,11 +1154,11 @@
  * Get a line number from 'obj' and convert it to vim's range.
  */
     static int
-tclgetlinenum(interp, obj, valueP, buf)
-    Tcl_Interp	*interp;
-    Tcl_Obj	*obj;
-    int		*valueP;
-    buf_T	*buf;
+tclgetlinenum(
+    Tcl_Interp	*interp,
+    Tcl_Obj	*obj,
+    int		*valueP,
+    buf_T	*buf)
 {
     int err, i;
 
@@ -1209,8 +1207,7 @@
  * Find the first window in the window list that displays the buffer.
  */
     static win_T *
-tclfindwin(buf)
-    buf_T *buf;
+tclfindwin(buf_T *buf)
 {
     win_T *win;
 
@@ -1226,11 +1223,11 @@
  * Do-it-all function for "::vim::command", "$buf command" and "$win command".
  */
     static int
-tcldoexcommand(interp, objc, objv, objn)
-    Tcl_Interp	*interp;
-    int		objc;
-    Tcl_Obj	*CONST objv[];
-    int		objn;
+tcldoexcommand(
+    Tcl_Interp	*interp,
+    int		objc,
+    Tcl_Obj	*CONST objv[],
+    int		objn)
 {
     tcl_info	saveinfo;
     int		err, flag, nobjs;
@@ -1284,11 +1281,11 @@
  * Do-it-all function for "::vim::option", "$buf option" and "$win option".
  */
     static int
-tclsetoption(interp, objc, objv, objn)
-    Tcl_Interp	*interp;
-    int		objc;
-    Tcl_Obj	*CONST objv[];
-    int		objn;
+tclsetoption(
+    Tcl_Interp	*interp,
+    int		objc,
+    Tcl_Obj	*CONST objv[],
+    int		objn)
 {
     int		err, nobjs, idx;
     char_u	*option;
@@ -1365,11 +1362,11 @@
  * Do-it-all function for "::vim::expr", "$buf expr" and "$win expr".
  */
     static int
-tclvimexpr(interp, objc, objv, objn)
-    Tcl_Interp	*interp;
-    int		objc;
-    Tcl_Obj	*CONST objv[];
-    int		objn;
+tclvimexpr(
+    Tcl_Interp	*interp,
+    int		objc,
+    Tcl_Obj	*CONST objv[],
+    int		objn)
 {
 #ifdef FEAT_EVAL
     char	*expr, *str;
@@ -1402,8 +1399,7 @@
  * Check for internal vim errors.
  */
     static int
-vimerror(interp)
-    Tcl_Interp *interp;
+vimerror(Tcl_Interp *interp)
 {
     if (got_int)
     {
@@ -1427,8 +1423,7 @@
  *   tclsetdelcmd() - add Tcl callback command to a vim object
  */
     static void
-delref(cref)
-    ClientData cref;
+delref(ClientData cref)
 {
     struct ref *ref = (struct ref *)cref;
 
@@ -1441,13 +1436,13 @@
 }
 
     static char *
-tclgetref(interp, refstartP, prefix, vimobj, proc)
-    Tcl_Interp	*interp;
-    void	**refstartP;	/* ptr to w_tcl_ref/b_tcl-ref member of
+tclgetref(
+    Tcl_Interp	*interp,
+    void	**refstartP,	/* ptr to w_tcl_ref/b_tcl-ref member of
 				   win_T/buf_T struct */
-    char	*prefix;	/* "win" or "buf" */
-    void	*vimobj;	/* win_T* or buf_T* */
-    Tcl_ObjCmdProc *proc;	/* winselfcmd or bufselfcmd */
+    char	*prefix,	/* "win" or "buf" */
+    void	*vimobj,	/* win_T* or buf_T* */
+    Tcl_ObjCmdProc *proc)	/* winselfcmd or bufselfcmd */
 {
     struct ref *ref, *unused = NULL;
     static char name[VARNAME_SIZE];
@@ -1501,27 +1496,23 @@
 }
 
     static char *
-tclgetwindow(interp, win)
-    Tcl_Interp	*interp;
-    win_T	*win;
+tclgetwindow(Tcl_Interp *interp, win_T *win)
 {
     return tclgetref(interp, &(win->w_tcl_ref), "win", (void *)win, winselfcmd);
 }
 
     static char *
-tclgetbuffer(interp, buf)
-    Tcl_Interp	*interp;
-    buf_T	*buf;
+tclgetbuffer(Tcl_Interp *interp, buf_T *buf)
 {
     return tclgetref(interp, &(buf->b_tcl_ref), "buf", (void *)buf, bufselfcmd);
 }
 
     static int
-tclsetdelcmd(interp, reflist, vimobj, delcmd)
-    Tcl_Interp	*interp;
-    struct ref	*reflist;
-    void	*vimobj;
-    Tcl_Obj	*delcmd;
+tclsetdelcmd(
+    Tcl_Interp	*interp,
+    struct ref	*reflist,
+    void	*vimobj,
+    Tcl_Obj	*delcmd)
 {
     if (reflist == &refsdeleted)
     {
@@ -1555,9 +1546,7 @@
 ********************************************/
 
     static int
-tcl_channel_close(instance, interp)
-    ClientData	instance;
-    Tcl_Interp	*interp UNUSED;
+tcl_channel_close(ClientData instance, Tcl_Interp *interp UNUSED)
 {
     int		err = 0;
 
@@ -1572,11 +1561,11 @@
 }
 
     static int
-tcl_channel_input(instance, buf, bufsiz, errptr)
-    ClientData	instance UNUSED;
-    char	*buf UNUSED;
-    int		bufsiz UNUSED;
-    int		*errptr;
+tcl_channel_input(
+    ClientData	instance UNUSED,
+    char	*buf UNUSED,
+    int		bufsiz UNUSED,
+    int		*errptr)
 {
 
     /* input is currently not supported */
@@ -1588,11 +1577,11 @@
 }
 
     static int
-tcl_channel_output(instance, buf, bufsiz, errptr)
-    ClientData	instance;
-    char	*buf;
-    int		bufsiz;
-    int		*errptr;
+tcl_channel_output(
+    ClientData	instance,
+    const char	*buf,
+    int		bufsiz,
+    int		*errptr)
 {
     char_u	*str;
     int		result;
@@ -1628,18 +1617,16 @@
 }
 
     static void
-tcl_channel_watch(instance, mask)
-    ClientData	instance UNUSED;
-    int		mask UNUSED;
+tcl_channel_watch(ClientData instance UNUSED, int mask UNUSED)
 {
     Tcl_SetErrno(EINVAL);
 }
 
     static int
-tcl_channel_gethandle(instance, direction, handleptr)
-    ClientData	instance UNUSED;
-    int		direction UNUSED;
-    ClientData	*handleptr UNUSED;
+tcl_channel_gethandle(
+    ClientData	instance UNUSED,
+    int		direction UNUSED,
+    ClientData	*handleptr UNUSED)
 {
     Tcl_SetErrno(EINVAL);
     return EINVAL;
@@ -1682,7 +1669,7 @@
  **********************************/
 
     static void
-tclupdatevars()
+tclupdatevars(void)
 {
     char varname[VARNAME_SIZE];	/* must be writeable */
     char *name;
@@ -1710,8 +1697,7 @@
 
 
     static int
-tclinit(eap)
-    exarg_T *eap;
+tclinit(exarg_T *eap)
 {
     char varname[VARNAME_SIZE];	/* Tcl_LinkVar requires writeable varname */
     char *name;
@@ -1820,8 +1806,7 @@
 }
 
     static void
-tclerrmsg(text)
-    char *text;
+tclerrmsg(char *text)
 {
     char *next;
 
@@ -1836,8 +1821,7 @@
 }
 
     static void
-tclmsg(text)
-    char *text;
+tclmsg(char *text)
 {
     char *next;
 
@@ -1852,7 +1836,7 @@
 }
 
     static void
-tcldelthisinterp()
+tcldelthisinterp(void)
 {
     if (!Tcl_InterpDeleted(tclinfo.interp))
 	Tcl_DeleteInterp(tclinfo.interp);
@@ -1874,8 +1858,7 @@
 }
 
     static int
-tclexit(error)
-    int error;
+tclexit(int error)
 {
     int newerr = OK;
 
@@ -1923,8 +1906,7 @@
  * ":tcl"
  */
     void
-ex_tcl(eap)
-    exarg_T *eap;
+ex_tcl(exarg_T *eap)
 {
     char_u	*script;
     int		err;
@@ -1950,8 +1932,7 @@
  * ":tclfile"
  */
     void
-ex_tclfile(eap)
-    exarg_T *eap;
+ex_tclfile(exarg_T *eap)
 {
     char *file = (char *)eap->arg;
     int err;
@@ -1969,8 +1950,7 @@
  * ":tcldo"
  */
     void
-ex_tcldo(eap)
-    exarg_T *eap;
+ex_tcldo(exarg_T *eap)
 {
     char	*script, *line;
     int		err, rs, re, lnum;
@@ -2045,8 +2025,7 @@
 }
 
     static void
-tcldelallrefs(ref)
-    struct ref *ref;
+tcldelallrefs(struct ref *ref)
 {
     struct ref	*next;
     int		err;
@@ -2083,8 +2062,7 @@
 }
 
     void
-tcl_buffer_free(buf)
-    buf_T *buf;
+tcl_buffer_free(buf_T *buf)
 {
     struct ref *reflist;
 
@@ -2104,8 +2082,7 @@
 
 #if defined(FEAT_WINDOWS) || defined(PROTO)
     void
-tcl_window_free(win)
-    win_T *win;
+tcl_window_free(win_T *win)
 {
     struct ref *reflist;