SIGSUSPEND(3P)            POSIX Programmer's Manual           SIGSUSPEND(3P)

PROLOG         top

       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.

NAME         top

       sigsuspend — wait for a signal

SYNOPSIS         top

       #include <signal.h>

       int sigsuspend(const sigset_t *sigmask);

DESCRIPTION         top

       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.

RETURN VALUE         top

       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.

ERRORS         top

       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.

EXAMPLES         top



       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.

RATIONALE         top

       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);
               return result;



SEE ALSO         top

       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)

COPYRIGHT         top

       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 .

       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 .

IEEE/The Open Group                 2013                      SIGSUSPEND(3P)