XtAppAddSignal, XtRemoveSignal, XtNoticeSignal - register and remove a signal
XtSignalId XtAppAddSignal(XtAppContext app_context,
XtSignalCallbackProc proc, XtPointer client_data);
void XtRemoveSignal(XtSignalId id);
void XtNoticeSignal(XtSignalId id);
- Specifies the application context.
- Specifies the argument that is to be passed to the specified procedure
when a signal has been raised.
- Specifies the ID returned from the corresponding XtAppAddSignal
- Specifies the procedure that is to be called when the signal has been
function initiates a mechanism for handling signals
within the context of the Intrinsics. Prior to establishing an operating
system dependent signal handler the application may call XtAppAddSignal
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
passing the id
returned by the call to
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
; the Intrinsics invoke the callback
whenever the flag is True
, and the flag is set to False
before the callback is invoked.
function is called to remove the specified Intrinsics
signal handler. The client should disable the source of the signal before
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface