XtAppAddSignal(3)

NAME

       XtAppAddSignal, XtRemoveSignal, XtNoticeSignal - register and remove a
       signal source

SYNTAX

       XtSignalId XtAppAddSignal(XtAppContext app_context, XtSignalCallback-
              Proc proc, XtPointer client_data);

       void XtRemoveSignal(XtSignalId id);

       void XtNoticeSignal(XtSignalId id);

ARGUMENTS

       app_context
                 Specifies the application context.

       client_data
                 Specifies the argument that is to be passed to the specified
                 procedure when a signal has been raised.

       id        Specifies the ID returned from the corresponding XtAppAdd-
                 Signal call.

       proc      Specifies the procedure that is to be called when the signal
                 has been raised.

DESCRIPTION

       The XtAppAddSignal function initiates a mechanism for handling signals
       within the context of the Intrinsics. Prior to establishing an operat-
       ing system dependent signal handler the application may call XtAppAdd-
       Signal and store the returned id in a place accessible to the signal
       handler.

       Upon receipt of a signal from the operating system, the application may
       call XtNoticeSignal passing the id returned by the call to XtAppAdd-
       Signal.

       XtNoticeSignal is the only Intrinsics function that can safely be
       called from a signal handler. If XtNoticeSignal is called multiple
       times before the Intrinsics are able to invoke the registered callback,
       the callback is only called once. Logically the Intrinsics maintain
       ``pending'' for each registered callback. This flag is initially False
       and is set to True by XtNoticeSignal; the Intrinsics invoke the call-
       back whenever the flag is True, and the flag is set to False just
       before the callback is invoked.

       The XtRemoveSignal function is called to remove the specified Intrin-
       sics signal handler. The client should disable the source of the signal
       before calling XtRemoveSignal.

SEE ALSO

       XtAppAddTimeOut(3Xt),XtAppAddInput(3Xt),XtAppAddWorkProc(3Xt)
       X Toolkit Intrinsics - C Language Interface
       Xlib - C Language X Interface

X Version 11                      libXt 1.0.5                XtAppAddSignal(3)