XtAppAddBlockHook(3Xt)

     NAME
          XtAppAddBlockHook, XtRemoveBlockHook - register a block hook
          procedure

     SYNTAX
          XtBlockHookId XtAppAddBlockHook(app_context, proc,
          client_data)
                XtAppContext app_context;
                XtBlockHookProc proc;
                XtPointer client_data;

          void XtRemoveBlockHook(idFP)
                XtBlockHookId id;

     ARGUMENTS
          app_context
                    Specifies the application context.

          proc      Specifies the block hook procedure.

          num_args  Specifies the application-specific data to be
                    passed to the block hook.

     DESCRIPTION
          XtAppAddBlockHook registers the specified procedure and
          returns an identifier for it.  The hook is called at any
          time in the future when the Intrinsics are about to block
          pending some input.

          Block hook procedures are removed automatically and the
          XtBlockHookId is destroyed when the application context in
          which they were added is destroyed.

          XtRemoveBlockHook removes the specified block hook procedure
          from the list in which it was registered.

     SEE ALSO
          X Toolkit Intrinsics - C Language Interface
          Xlib - C Language X Interface