XtAppAddSignal(3) XT FUNCTIONS 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(3),XtAppAddInput(3),XtAppAddWorkProc(3)
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface
X Version 11 libXt 1.0.5 XtAppAddSignal(3)
Mac OS X 10.6 X11 - Generated Sun Mar 7 12:32:54 CST 2010