XtCreateApplicationContext - Man Page
create, destroy, and obtain an application context
void XtDestroyApplicationContext(XtAppContext app_context);
XtAppContext XtWidgetToApplicationContext(Widget w);
Specifies the application context.
Specifies the widget that you want the application context for.
The XtCreateApplicationContext function returns an application context, which is an opaque type. Every application must have at least one application context.
The XtDestroyApplicationContext function destroys the specified application context as soon as it is safe to do so. If called from with an event dispatch (for example, a callback procedure), XtDestroyApplicationContext does not destroy the application context until the dispatch is complete.
The XtWidgetToApplicationContext function returns the application context for the specified widget.
The XtToolkitInitialize function initializes the Intrinsics internals. If XtToolkitInitialize was previously called it returns immediately.
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface
The man pages XtDestroyApplicationContext(3), XtToolkitInitialize(3) and XtWidgetToApplicationContext(3) are aliases of XtCreateApplicationContext(3).