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'\"
'\" Copyright (c) 1994 The Regents of the University of California.
'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
.TH Tk_Main 3 4.0 Tk "Tk Library Procedures"
.so man.macros
.BS
.SH NAME
Tk_Main \- main program for Tk-based applications
.SH SYNOPSIS
.nf
\fB#include <tk.h>\fR
.sp
\fBTk_Main\fR(\fIargc, argv, appInitProc\fR)
.SH ARGUMENTS
.AS Tcl_AppInitProc *appInitProc
.AP int argc in
Number of elements in \fIargv\fR.
.AP char *argv[] in
Array of strings containing command-line arguments. On Windows, when
using -DUNICODE, the parameter type changes to wchar_t *.
.AP Tcl_AppInitProc *appInitProc in
Address of an application-specific initialization procedure.
The value for this argument is usually \fBTcl_AppInit\fR.
.BE
.SH DESCRIPTION
.PP
\fBTk_Main\fR acts as the main program for most Tk-based applications.
Starting with Tk 4.0 it is not called \fBmain\fR anymore because it
is part of the Tk library and having a function \fBmain\fR
in a library (particularly a shared library) causes problems on many
systems.
Having \fBmain\fR in the Tk library would also make it hard to use
Tk in C++ programs, since C++ programs must have special C++
\fBmain\fR functions.
.PP
Normally each application contains a small \fBmain\fR function that does
nothing but invoke \fBTk_Main\fR.
\fBTk_Main\fR then does all the work of creating and running a
\fBwish\fR-like application.
.PP
When it is has finished its own initialization, but before
it processes commands, \fBTk_Main\fR calls the procedure given by
the \fIappInitProc\fR argument.  This procedure provides a
.QW hook
for the application to perform its own initialization, such as defining
application-specific commands.  The procedure must have an interface
that matches the type \fBTcl_AppInitProc\fR:
.CS
typedef int \fBTcl_AppInitProc\fR(
        Tcl_Interp *\fIinterp\fR);
.CE
\fIAppInitProc\fR is almost always a pointer to \fBTcl_AppInit\fR;
for more details on this procedure, see the documentation
for \fBTcl_AppInit\fR.
.PP
\fBTk_Main\fR functions much the same as \fBTcl_Main\fR.  In particular,
\fBTk_Main\fR supports both an interactive mode and a startup script
mode, with the file name and encoding of a startup script under the
control of the \fBTcl_SetStartupScript\fR and \fBTcl_GetStartupScript\fR
routines. However it calls \fBTk_MainLoop\fR after processing any
supplied script, and in interactive uses events registered with
\fBTcl_CreateFileHandler\fR to process user input.
.SH "SEE ALSO"
Tcl_DoOneEvent(3)
.SH KEYWORDS
application-specific initialization, command-line arguments, main program