XtAppSetExitFlag, XtAppGetExitFlag - thread support functions
#include <X11/Intrinsic.h>
void XtAppSetExitFlag(XtAppContext app_context);
Boolean XtAppGetExitFlag(XtAppContext app_context);
Specifies the application context.
To indicate that an application context should exit, use XtAppSetExitFlag.
To test the exit status of an application context, use XtAppGetExitFlag.
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface