## Tcl8.5.14/Tk8.5.14 Documentation > TkLib > Tk_Main

### Tcl/Tk Applications | Tcl Commands | Tk Commands | Tcl Library | Tk Library

### NAME

Tk_Main - main program for Tk-based applications

### SYNOPSIS

#include <tk8.5/tk.h>
Tk_Main(argc, argv, appInitProc)

### ARGUMENTS

int argc (in)
  Number of elements in argv.

char *argv[] (in)
  Array of strings containing command-line arguments.

Tcl_AppInitProc *appInitProc (in)
  Address of an application-specific initialization procedure. The value for this argument is usually Tcl_AppInit.

### DESCRIPTION

Tk_Main acts as the main program for most Tk-based applications. Starting with Tk 4.0 it is not called main anymore because it is part of the Tk library and having a function main in a library (particularly a shared library) causes problems on many systems. Having main in the Tk library would also make it hard to use Tk in C++ programs, since C++ programs must have special C++ main functions.

Normally each application contains a small main function that does nothing but invoke Tk_Main. Tk_Main then does all the work of creating and running a wish-like application.

When it is has finished its own initialization, but before it processes commands, Tk_Main calls the procedure given by the appInitProc argument. This procedure provides a “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 Tcl_AppInitProc:

    typedef int Tcl_AppInitProc(Tcl_Interp *interp);

AppInitProc is almost always a pointer to Tcl_AppInit; for more details on this procedure, see the documentation for Tcl_AppInit.

### KEYWORDS

application-specific initialization, command-line arguments, main program
Copyright © 1995-1997 Roger E. Critchlow Jr. Copyright © 1994 The Regents of the University of California. Copyright © 1994-1996 Sun Microsystems, Inc.