1.\" $OpenBSD: sigsuspend.2,v 1.14 2017/05/29 09:40:02 deraadt Exp $ 2.\" $NetBSD: sigsuspend.2,v 1.4 1995/02/27 12:37:46 cgd Exp $ 3.\" 4.\" Copyright (c) 1983, 1991, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)sigsuspend.2 8.1 (Berkeley) 6/4/93 32.\" 33.Dd $Mdocdate: May 29 2017 $ 34.Dt SIGSUSPEND 2 35.Os 36.Sh NAME 37.Nm sigsuspend 38.Nd atomically change the signal mask and wait for interrupt 39.Sh SYNOPSIS 40.In signal.h 41.Ft int 42.Fn sigsuspend "const sigset_t *sigmask" 43.Sh DESCRIPTION 44.Fn sigsuspend 45temporarily changes the blocked signal mask to the set to which 46.Fa sigmask 47points, 48and then waits for a signal to arrive; 49on return the previous set of masked signals is restored. 50The signal mask set 51is usually empty to indicate that all 52signals are to be unblocked for the duration of the call. 53.Pp 54In normal usage, a signal is blocked using 55.Xr sigprocmask 2 56to begin a critical section, variables modified on the occurrence 57of the signal are examined to determine that there is no work 58to be done, and the process pauses awaiting work by using 59.Fn sigsuspend 60with the previous mask returned by 61.Xr sigprocmask 2 . 62.Sh RETURN VALUES 63The 64.Fn sigsuspend 65function always terminates by being interrupted, returning \-1 with 66.Va errno 67set to 68.Er EINTR . 69.Sh SEE ALSO 70.Xr sigaction 2 , 71.Xr sigprocmask 2 , 72.Xr sigaddset 3 73.Sh STANDARDS 74The 75.Fn sigsuspend 76function call 77conforms to 78.St -p1003.1-2008 . 79