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



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult the corresponding Linux manual page for details of Linux behavior), or the  interface  may  not  be  implemented  on
       Linux.

NAME
       sigsuspend - wait for a signal

SYNOPSIS
       #include <signal.h>

       int sigsuspend(const sigset_t *sigmask);


DESCRIPTION
       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
       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
       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
       None.

APPLICATION USAGE
       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
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       Signal Concepts, pause(), sigaction(), sigaddset(), sigdelset(), sigemptyset(), sigfillset(), the Base Definitions volume
       of IEEE Std 1003.1-2001, <signal.h>

COPYRIGHT
       Portions  of  this  text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for
       Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6,  Copy-
       right (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. 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.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                SIGSUSPEND(3P)