SIGSUSPEND(P) POSIX Programmer's Manual SIGSUSPEND(P)
sigsuspend - wait for a signal
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 comple-
tion return value. If a return occurs, -1 shall be returned and errno set to indicate the
The sigsuspend() function shall fail if:
EINTR A signal is caught by the calling process and control is returned from the signal-
The following sections are informative.
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 sec-
tion and needs to wait for the previously blocked signal(s), it pauses by calling sigsus-
pend() with the mask that was returned by the sigprocmask() call.
Signal Concepts , pause() , sigaction() , sigaddset() , sigdelset() , sigemptyset() , sig-
fillset() , the Base Definitions volume of IEEE Std 1003.1-2001, <signal.h>
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, Copyright (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 orig-
inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 SIGSUSPEND(P)