#include <tcl.h> Tcl_Main(argc, argv, appInitProc)
Tcl_Main acts as the main program for most Tcl-based applications. Starting with Tcl 7.4 it is not called main anymore because it is part of the Tcl library and having a function main in a library (particularly a shared library) causes problems on many systems. Having main in the Tcl library would also make it hard to use Tcl 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 Tcl_Main. Tcl_Main then does all the work of creating and running a tclsh-like application.
When it is has finished its own initialization, but before it processes commands, Tcl_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: