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: src/lib/libc/sys/sigsuspend.2,v 1.9.2.4 2001/12/14 18:34:01 ru Exp $ 30.\" $DragonFly: src/lib/libc/sys/sigsuspend.2,v 1.4 2006/10/21 22:17:09 swildner Exp $ 31.\" 32.Dd May 16, 1995 33.Dt SIGSUSPEND 2 34.Os 35.Sh NAME 36.Nm sigsuspend 37.Nd atomically release blocked signals and wait for interrupt 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In signal.h 42.Ft int 43.Fn sigsuspend "const sigset_t *sigmask" 44.Sh DESCRIPTION 45.Fn Sigsuspend 46temporarily changes the blocked signal mask to the set to which 47.Fa sigmask 48points, 49and then waits for a signal to arrive; 50on return the previous set of masked signals is restored. 51The signal mask set 52is usually empty to indicate that all 53signals are to be unblocked for the duration of the call. 54.Pp 55In normal usage, a signal is blocked using 56.Xr sigprocmask 2 57to begin a critical section, variables modified on the occurrence 58of the signal are examined to determine that there is no work 59to be done, and the process pauses awaiting work by using 60.Fn sigsuspend 61with the previous mask returned by 62.Xr sigprocmask 2 . 63.Sh RETURN VALUES 64The 65.Fn sigsuspend 66function 67always terminates by being interrupted, returning -1 with 68.Va errno 69set to 70.Er EINTR . 71.Sh SEE ALSO 72.Xr sigaction 2 , 73.Xr sigprocmask 2 , 74.Xr sigsetops 3 75.Sh STANDARDS 76The 77.Fn sigsuspend 78function call is expected to conform to 79.St -p1003.1-90 . 80