HP-UX Reference (11i v1 05/09) - 2 System Calls (vol 5)

s
sigsuspend(2) sigsuspend(2)
NAME
sigsuspend - wait for a signal
SYNOPSIS
#include <signal.h>
int sigsuspend(const sigset_t *sigmask);
DESCRIPTION
The sigsuspend() function replaces the process’ current signal mask with the set of signals pointed to
by sigmask and then suspends the process until delivery of a signal whose action is either to execute a
signal-catching function or to terminate the process.
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
sigsuspend() call.
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
Since
sigsuspend() suspends process 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
The sigsuspend() function will fail if:
[EINTR] A signal is caught by the calling process and control is returned from the
signal-catching function.
APPLICATION USAGE
Threads Considerations
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 signal.
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 sigwait(2) is
recommended instead of
sigsuspend() for multi-threaded applications.
For more information regarding signals and threads, refer to signal(5).
LWP (Lightweight Processes) Considerations
sigsuspend() modifies only the calling LWP’s signal mask and suspends only the calling LWP until
receipt of a signal.
SEE ALSO
pause(2), sigaction(2), sigwait(2), sigsetops(3C), <signal.h>.
CHANGE HISTORY
First released in Issue 3.
Entry included for alignment with the POSIX.1-1988 standard.
Issue 4
The following change is incorporated for alignment with the ISO POSIX-1 standard:
• The type of the argument sigmask is changed from sigset_t* to type const sigset_t*.
Another change is incorporated as follows:
• The term "signal handler" is changed to "signal-catching function."
HP-UX 11i Version 1: September 2005 − 1 − Hewlett-Packard Company Section 2−−389