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.\" from: @(#)sigblock.2 8.1 (Berkeley) 6/2/93 29.\" $NetBSD: sigblock.3,v 1.17 2003/08/07 16:42:40 agc Exp $ 30.\" 31.Dd August 10, 2002 32.Dt SIGBLOCK 3 33.Os 34.Sh NAME 35.Nm sigblock 36.Nd block signals 37.Sh LIBRARY 38.Lb libc 39.Sh SYNOPSIS 40.In signal.h 41.Ft int 42.Fn sigblock "int mask" 43.Ft int 44.Fn sigmask signum 45.Sh DESCRIPTION 46.Bf -symbolic 47This interface is made obsolete by: 48.Xr sigprocmask 2 . 49.Ef 50.Pp 51.Fn sigblock 52adds the signals specified in 53.Fa mask 54to the set of signals currently 55being blocked from delivery. 56Signals are blocked if the 57corresponding bit in 58.Fa mask 59is a 1; the macro 60.Fn sigmask 61is provided to construct the mask for a given 62.Fa signum . 63.Pp 64It is not possible to block 65.Dv SIGKILL 66or 67.Dv SIGSTOP ; 68this restriction is silently 69imposed by the system. 70.Sh RETURN VALUES 71The previous set of masked signals is returned. 72.Sh EXAMPLES 73The following example using 74.Fn sigblock : 75.Bd -literal -offset indent 76int omask; 77 78omask = sigblock(sigmask(SIGINT) | sigmask(SIGHUP)); 79.Ed 80.Pp 81Becomes: 82.Bd -literal -offset indent 83sigset_t set, oset; 84 85sigemptyset(&set); 86sigaddset(&set, SIGINT); 87sigaddset(&set, SIGHUP); 88sigprocmask(SIG_BLOCK, &set, &oset); 89.Ed 90.Pp 91Another use of 92.Fn sigblock 93is to get the current set of masked signals without changing what 94is actually blocked. 95Instead of: 96.Bd -literal -offset indent 97int set; 98 99set = sigblock(0); 100.Ed 101.Pp 102Use the following: 103.Bd -literal -offset indent 104sigset_t set; 105 106sigprocmask(SIG_BLOCK, NULL, &set); 107.Ed 108.Sh SEE ALSO 109.Xr kill 2 , 110.Xr sigaction 2 , 111.Xr sigprocmask 2 , 112.Xr sigsetmask 3 , 113.Xr sigsetops 3 114.Sh HISTORY 115The 116.Fn sigblock 117function call appeared in 118.Bx 4.2 119and has been deprecated. 120