1.\" $NetBSD: sigsuspend.2,v 1.4 1995/02/27 12:37:46 cgd Exp $ 2.\" 3.\" Copyright (c) 1983, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)sigsuspend.2 8.1 (Berkeley) 6/4/93 35.\" 36.Dd June 4, 1993 37.Dt SIGSUSPEND 2 38.Os 39.Sh NAME 40.Nm sigsuspend 41.Nd atomically release blocked signals and wait for interrupt 42.Sh SYNOPSIS 43.Fd #include <signal.h> 44.Ft int 45.Fn sigsuspend "const sigset_t *sigmask" 46.Sh DESCRIPTION 47.Fn Sigsuspend 48temporarily changes the blocked signal mask to the set to which 49.Fa sigmask 50points, 51and then waits for a signal to arrive; 52on return the previous set of masked signals is restored. 53The signal mask set 54is usually empty to indicate that all 55signals are to be unblocked for the duration of the call. 56.Pp 57In normal usage, a signal is blocked using 58.Xr sigprocmask 2 59to begin a critical section, variables modified on the occurrence 60of the signal are examined to determine that there is no work 61to be done, and the process pauses awaiting work by using 62.Fn sigsuspend 63with the previous mask returned by 64.Xr sigprocmask . 65.Sh RETURN VALUES 66The 67.Fn sigsuspend 68function 69always terminates by being interrupted, returning -1 with 70.Va errno 71set to 72.Dv EINTR . 73.Sh SEE ALSO 74.Xr sigprocmask 2 , 75.Xr sigaction 2 , 76.Xr sigsetops 3 77.Sh STANDARDS 78The 79.Nm sigsupend 80function call 81conforms to 82.St -p1003.1-88 . 83