1.\" $NetBSD: sigtimedwait.2,v 1.3 2003/04/16 13:34:57 wiz Exp $ 2.\" 3.\" Copyright (c) 2003 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Jaromir Dolecek. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 3. All advertising materials mentioning features or use of this software 18.\" must display the following acknowledgement: 19.\" This product includes software developed by the NetBSD 20.\" Foundation, Inc. and its contributors. 21.\" 4. Neither the name of The NetBSD Foundation nor the names of its 22.\" contributors may be used to endorse or promote products derived 23.\" from this software without specific prior written permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 26.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 29.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35.\" POSSIBILITY OF SUCH DAMAGE. 36.\" 37.Dd February 10, 2003 38.Dt SIGTIMEDWAIT 2 39.Os 40.Sh NAME 41.Nm sigtimedwait , 42.Nm sigwaitinfo , 43.Nm sigwait 44.Nd wait for queued signals 45.Sh LIBRARY 46.Lb libc 47.Sh SYNOPSIS 48.In signal.h 49.Ft int 50.Fn sigtimedwait "const sigset_t * restrict set" "siginfo_t * restrict info" "const struct timespec * restrict timeout" 51.Ft int 52.Fn sigwaitinfo "const sigset_t * restrict set" "siginfo_t * restrict info" 53.Ft int 54.Fn sigwait "const sigset_t * restrict set" "int * restrict sig" 55.Sh DESCRIPTION 56.Fn sigwaitinfo 57and 58.Fn sigwait 59return the first pending signal from the set specified by 60.Fa set . 61Should multiple signals from 62.Fa set 63be pending, the lowest numbered one is returned. 64The selection order between realtime and non-realtime signals is unspecified. 65If there is no signal from 66.Ar set 67pending at the time of the call, the calling thread 68is suspended until one of the specified signals is generated. 69.Pp 70.Fn sigtimedwait 71is exactly equal to 72.Fn sigwaitinfo , 73except 74.Fa timeout 75specifies the maximum time interval for which the calling thread will 76be suspended. 77If 78.Fa timeout 79is zero (tv_sec == tv_nsec == 0), 80.Fn sigtimedwait 81only checks the currently pending signals and returns immediately. 82If 83.Dv NULL 84is used for 85.Fa timeout , 86.Fn sigtimedwait 87behaves exactly like 88.Fn sigwaitinfo 89in all regards. 90.Pp 91If several threads are waiting for a given signal, exactly one of them 92returns from the signal wait when the signal is generated. 93.Pp 94Behaviour of these functions is unspecified if any of the signals in 95.Fa set 96are unblocked at the time these functions are called. 97.Sh RETURN VALUES 98Upon successful completion 99.Fa info 100is updated with signal information, and the function returns 0. 101Otherwise, \-1 is returned and the global variable 102.Va errno 103indicates the error. 104.Sh ERRORS 105.Fn sigwaitinfo 106and 107.Fn sigwait 108always succeed. 109.Pp 110.Fn sigtimedwait 111will fail and the 112.Fa info 113pointer will remain unchanged if: 114.Bl -tag -width Er 115.It Bq Er EAGAIN 116No signal specified in 117.Fa set 118was generated in the specified 119.Fa timeout . 120.El 121.Pp 122.Fn sigtimedwait 123may also fail if: 124.Bl -tag -width Er 125.It Bq Er EINVAL 126The specified 127.Fa timeout 128was invalid. 129.El 130.Pp 131This error is only checked if no signal from 132.Fa set 133is pending and it would be necessary to wait. 134.Sh SEE ALSO 135.Xr sigaction 2 , 136.Xr sigprocmask 2 , 137.Xr signal 7 138.Sh STANDARDS 139The functions 140.Fn sigtimedwait , 141.Fn sigwaitinfo , 142and 143.Fn sigwait 144conform to 145.St -p1003.1-2001 . 146.Sh HISTORY 147The 148.Fn sigtimedwait , 149.Fn sigwaitinfo , 150and 151.Fn sigwait 152functions appeared in 153.Nx 2.0 . 154.Sh AUTHORS 155The initial 156.Nx 157implementation of the signal wait functions was written by 158.An Jaromir Dolecek 159.Aq jdolecek@NetBSD.org . 160