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SIGSUSPEND(3P) POSIX Programmer's Manual SIGSUSPEND(3P)
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
sigsuspend — wait for a signal
#include <signal.h>
int sigsuspend(const sigset_t *sigmask);
The sigsuspend() function shall replace the current signal mask of
the calling thread with the set of signals pointed to by sigmask and
then suspend the thread until delivery of a signal whose action is
either to execute a signal-catching function or to terminate the
process. This shall 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() shall
never return. If the action is to execute a signal-catching function,
then sigsuspend() shall 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.
Since sigsuspend() suspends thread execution indefinitely, there is
no successful completion return value. If a return occurs, −1 shall
be returned and errno set to indicate the error.
The sigsuspend() function shall fail if:
EINTR A signal is caught by the calling process and control is
returned from the signal-catching function.
The following sections are informative.
None.
Normally, at the beginning of a critical code section, a specified
set of signals is blocked using the sigprocmask() function. When the
thread has completed the critical section and needs to wait for the
previously blocked signal(s), it pauses by calling sigsuspend() with
the mask that was returned by the sigprocmask() call.
Code which wants to avoid the ambiguity of the signal mask for thread
cancellation handlers can install an additional cancellation handler
which resets the signal mask to the expected value.
void cleanup(void *arg)
{
sigset_t *ss = (sigset_t *) arg;
pthread_sigmask(SIG_SETMASK, ss, NULL);
}
int call_sigsuspend(const sigset_t *mask)
{
sigset_t oldmask;
int result;
pthread_sigmask(SIG_SETMASK, NULL, &oldmask);
pthread_cleanup_push(cleanup, &oldmask);
result = sigsuspend(sigmask);
pthread_cleanup_pop(0);
return result;
}
None.
Section 2.4, Signal Concepts, pause(3p), sigaction(3p),
sigaddset(3p), sigdelset(3p), sigemptyset(3p), sigfillset(3p)
The Base Definitions volume of POSIX.1‐2008, signal.h(0p)
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) In the event of any discrepancy between this version and
the original IEEE and The Open Group Standard, the original IEEE and
The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 SIGSUSPEND(3P)
Pages that refer to this page: signal.h(0p), pause(3p), pthread_sigmask(3p), sigaction(3p), sigaddset(3p), sigdelset(3p), sigemptyset(3p), sigfillset(3p), sighold(3p), sigismember(3p), siglongjmp(3p), signal(3p), sigsetjmp(3p), sigtimedwait(3p), sigwait(3p)