tcldoc Tcl/Tk 9.0.4
/

Home › Tk Library Procedures Tk

Tk_Main C API

Main program for Tk-based applications

literal type exactly as shown argument replace with your value ?optional? may be omitted

Synopsis#

#include <tk.h>

Tk_Main(argc, argv, appInitProc)#

Arguments#

Tcl_Size argc (in)

Number of elements in argv.

char *argv[] (in)

Array of strings containing command-line arguments. On Windows, when using -DUNICODE, the parameter type changes to wchar_t *.

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.

Tk_Main functions much the same as Tcl_Main. In particular, Tk_Main 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 Tcl_SetStartupScript and Tcl_GetStartupScript routines. However it calls Tk_MainLoop after processing any supplied script, and in interactive uses events registered with Tcl_CreateFileHandler to process user input.

Keywords#

application-specific initialization · command-line arguments · main program

Copyright#