1.\" $NetBSD: sigsuspend.2,v 1.13 2002/02/08 01:28:22 ross 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 8.2 (Berkeley) 5/16/95 35.\" 36.Dd May 16, 1995 37.Dt SIGSUSPEND 2 38.Os 39.Sh NAME 40.Nm sigsuspend 41.Nd atomically release blocked signals and wait for interrupt 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.Fd #include \*[Lt]signal.h\*[Gt] 46.Ft int 47.Fn sigsuspend "const sigset_t *sigmask" 48.Sh DESCRIPTION 49.Fn sigsuspend 50temporarily changes the blocked signal mask to the set to which 51.Fa sigmask 52points, 53and then waits for a signal to arrive; 54on return the previous set of masked signals is restored. 55The signal mask set 56is usually empty to indicate that all 57signals are to be unblocked for the duration of the call. 58.Pp 59In normal usage, a signal is blocked using 60.Xr sigprocmask 2 61to begin a critical section, variables modified on the occurrence 62of the signal are examined to determine that there is no work 63to be done, and the process pauses awaiting work by using 64.Fn sigsuspend 65with the previous mask returned by 66.Xr sigprocmask 2 . 67.Sh RETURN VALUES 68The 69.Fn sigsuspend 70function 71always terminates by being interrupted, returning -1 with 72.Va errno 73set to 74.Er EINTR . 75.Sh SEE ALSO 76.Xr sigaction 2 , 77.Xr sigprocmask 2 , 78.Xr sigsetops 3 , 79.Xr signal 7 80.Sh STANDARDS 81The 82.Nm sigsuspend 83function call conforms to 84.St -p1003.1-90 . 85