find the main window for an application

## NAME

Tk_MainWindow - find the main window for an application

## SYNOPSIS

#include <tk.h>

Tk_Window Tk_MainWindow(interp)

## ARGUMENTS

`Tcl_Interp *interp` (in/out)
  Interpreter associated with the application.

## DESCRIPTION

If interp is associated with a Tk application then Tk_MainWindow returns the application's main window. If there is no Tk application associated with interp then Tk_MainWindow returns NULL and leaves an error message in interp->result.

## KEYWORDS

application, main window