NAME [Toc] [Back]
sigsuspend - wait for a signal
SYNOPSIS [Toc] [Back]
int sigsuspend(const sigset_t *sigmask);
DESCRIPTION [Toc] [Back]
The sigsuspend() function replaces the current signal mask of the
calling thread with the set of signals pointed to by sigmask and then
suspends the thread until delivery of a signal whose action is either
to execute a signal-catching function or to terminate the process.
This will not cause any other signals that may have been pending on
the process to become pending on the thread.
If the action is to terminate the process then sigsuspend() will never
return. If the action is to execute a signal-catching function, then
sigsuspend() will return after the signal-catching function returns,
with the signal mask restored to the set that existed prior to the
It is not possible to block signals that cannot be ignored. This is
enforced by the system without causing an error to be indicated.
RETURN VALUE [Toc] [Back]
Since sigsuspend() suspends thread execution indefinitely, there is no
successful completion return value. If a return occurs, -1 is returned
and errno is set to indicate the error.
ERRORS [Toc] [Back]
The sigsuspend() function will fail if:
[EINTR] A signal is caught by the calling process and
control is returned from the signal-catching
[EFAULT] sigmask points to an invalid address. The
reliable detection of this error is
APPLICATION USAGE [Toc] [Back]
Since blocked signal masks are maintained at the thread level,
sigsuspend() modifies only the calling thread's blocked signal mask.
sigsuspend() suspends only the calling thread until it receives a
If other threads in the process do not block the signal, the signal
may be delivered to another thread in the process and the thread in
sigsuspend() may continue waiting. For this reason, the use of
Hewlett-Packard Company - 1 - HP-UX 11i Version 2: August 2003
sigwait(2) is recommended instead of sigsuspend() for multi-threaded
For more information regarding signals and threads, refer to
LWP (Lightweight Processes) Considerations [Toc] [Back]
sigsuspend() modifies only the calling LWP's signal mask and suspends
only the calling LWP until receipt of a signal.
AUTHOR [Toc] [Back]
sigsuspend() was derived from the IEEE POSIX 1003.1-1988 Standard.
SEE ALSO [Toc] [Back]
pause(2), sigaction(2), sigpending(2), sigprocmask(2), sigsetops(3C),
CHANGE HISTORY [Toc] [Back]
First released in Issue 3.
Entry included for alignment with the POSIX.1-1988 standard.
STANDARDS CONFORMANCE [Toc] [Back]
sigsuspend(): AES, SVID3, XPG3, XPG4, FIPS 151-2, POSIX.1
Hewlett-Packard Company - 2 - HP-UX 11i Version 2: August 2003 [ Back ]