## Tcl8.6.0/Tk8.6.0 Documentation > Tk C API, version 8.6.0 > MainLoop

### Tcl/Tk Applications | Tcl Commands | Tk Commands | [incr Tcl] Package Commands | SQLite Package Commands | TDBC Package Commands | tdbc::mysql Package Commands | tdbc::odbc Package Commands | tdbc::postgres Package Commands | tdbc::sqlite3 Package Commands | Thread Package Commands | Tcl C API | Tk C API | [incr Tcl] Package C API | TDBC Package C API

### NAME

Tk_MainLoop — loop for events until all windows are deleted

### SYNOPSIS

#include <tk8.6/tk.h>
Tk_MainLoop()

### DESCRIPTION

Tk_MainLoop is a procedure that loops repeatedly calling Tcl_DoOneEvent. It returns only when there are no applications left in this process (i.e. no main windows exist anymore). Most windowing applications will call Tk_MainLoop after initialization; the main execution of the application will consist entirely of callbacks invoked via Tcl_DoOneEvent.

### KEYWORDS

application, event, main loop
Copyright © 1990-1992 The Regents of the University of California. Copyright © 1994-1996 Sun Microsystems, Inc.