1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)sigsuspend.2 8.2 (Berkeley) 5/16/95 29.\" $FreeBSD$ 30.\" 31.Dd August 16, 2013 32.Dt SIGSUSPEND 2 33.Os 34.Sh NAME 35.Nm sigsuspend 36.Nd atomically release blocked signals and wait for interrupt 37.Sh LIBRARY 38.Lb libc 39.Sh SYNOPSIS 40.In signal.h 41.Ft int 42.Fn sigsuspend "const sigset_t *sigmask" 43.Sh DESCRIPTION 44The 45.Fn sigsuspend 46system call 47temporarily changes the blocked signal mask to the set to which 48.Fa sigmask 49points, 50and then waits for a signal to arrive; 51on return the previous set of masked signals is restored. 52The signal mask set 53is usually empty to indicate that all 54signals are to be unblocked for the duration of the call. 55.Pp 56In normal usage, a signal is blocked using 57.Xr sigprocmask 2 58to begin a critical section, variables modified on the occurrence 59of the signal are examined to determine that there is no work 60to be done, and the process pauses awaiting work by using 61.Fn sigsuspend 62with the previous mask returned by 63.Xr sigprocmask 2 . 64.Sh RETURN VALUES 65The 66.Fn sigsuspend 67system call 68always terminates by being interrupted, returning -1 with 69.Va errno 70set to 71.Er EINTR . 72.Sh SEE ALSO 73.Xr pselect 2 , 74.Xr sigaction 2 , 75.Xr sigpending 2 , 76.Xr sigprocmask 2 , 77.Xr sigtimedwait 2 , 78.Xr sigwait 2 , 79.Xr sigwaitinfo 2 , 80.Xr sigsetops 3 81.Sh STANDARDS 82The 83.Fn sigsuspend 84system call is expected to conform to 85.St -p1003.1-90 . 86