Table of Contents
XtAppAddSignal, XtRemoveSignal, XtNoticeSignal
- register and remove a signal source
- XtSignalId XtAppAddSignal(XtAppContext
app_context, XtSignalCallbackProc
- proc, XtPointer client_data);
- void XtRemoveSignal(XtSignalId
id);
- void XtNoticeSignal(XtSignalId id);
- 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 XtAppAddSignal call.
- proc
- Specifies
the procedure that is to be called when the signal has been raised.
The
XtAppAddSignal 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
XtNoticeSignal passing the id returned by the call to XtAppAddSignal.
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 callback 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 Intrinsics
signal handler. The client should disable the source of the signal before
calling XtRemoveSignal.
XtAppAddTimeOut(3Xt)
,XtAppAddInput(3Xt)
,XtAppAddWorkProc(3Xt)
X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface
Table of Contents