1c5e7e03aSRuslan Ermilov.\" Copyright (C) 2000 Jason Evans <jasone@FreeBSD.org>. 2b0a1b4f8SJason Evans.\" All rights reserved. 3b0a1b4f8SJason Evans.\" 4b0a1b4f8SJason Evans.\" Redistribution and use in source and binary forms, with or without 5b0a1b4f8SJason Evans.\" modification, are permitted provided that the following conditions 6b0a1b4f8SJason Evans.\" are met: 7b0a1b4f8SJason Evans.\" 1. Redistributions of source code must retain the above copyright 8b0a1b4f8SJason Evans.\" notice(s), this list of conditions and the following disclaimer as 9b0a1b4f8SJason Evans.\" the first lines of this file unmodified other than the possible 10b0a1b4f8SJason Evans.\" addition of one or more copyright notices. 11b0a1b4f8SJason Evans.\" 2. Redistributions in binary form must reproduce the above copyright 12b0a1b4f8SJason Evans.\" notice(s), this list of conditions and the following disclaimer in 13b0a1b4f8SJason Evans.\" the documentation and/or other materials provided with the 14b0a1b4f8SJason Evans.\" distribution. 15b0a1b4f8SJason Evans.\" 16b0a1b4f8SJason Evans.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY 17b0a1b4f8SJason Evans.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18b0a1b4f8SJason Evans.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19b0a1b4f8SJason Evans.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE 20b0a1b4f8SJason Evans.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21b0a1b4f8SJason Evans.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22b0a1b4f8SJason Evans.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR 23b0a1b4f8SJason Evans.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 24b0a1b4f8SJason Evans.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 25b0a1b4f8SJason Evans.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 26b0a1b4f8SJason Evans.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27b0a1b4f8SJason Evans.\" 28b0a1b4f8SJason Evans.\" $FreeBSD$ 2926b6c45aSRuslan Ermilov.\" 30*49ba8a68SJilles Tjoelker.Dd January 28, 2015 31b0a1b4f8SJason Evans.Dt SEM_POST 3 32b0a1b4f8SJason Evans.Os 33b0a1b4f8SJason Evans.Sh NAME 34b0a1b4f8SJason Evans.Nm sem_post 35b0a1b4f8SJason Evans.Nd increment (unlock) a semaphore 36d8a78688SAlexey Zelkin.Sh LIBRARY 37fccedf06SRuslan Ermilov.Lb libc 38b0a1b4f8SJason Evans.Sh SYNOPSIS 3932eef9aeSRuslan Ermilov.In semaphore.h 40b0a1b4f8SJason Evans.Ft int 41b0a1b4f8SJason Evans.Fn sem_post "sem_t *sem" 42b0a1b4f8SJason Evans.Sh DESCRIPTION 43b0a1b4f8SJason EvansThe 44b0a1b4f8SJason Evans.Fn sem_post 45b0a1b4f8SJason Evansfunction increments (unlocks) the semaphore pointed to by 46b0a1b4f8SJason Evans.Fa sem . 47b0a1b4f8SJason EvansIf there are threads blocked on the semaphore when 48b0a1b4f8SJason Evans.Fn sem_post 49b0a1b4f8SJason Evansis called, then the highest priority thread that has been blocked the longest on 50b0a1b4f8SJason Evansthe semaphore will be allowed to return from 51b0a1b4f8SJason Evans.Fn sem_wait . 52b167c9a5SJason Evans.Pp 53ab165955SPhilippe CharnierThe 54b167c9a5SJason Evans.Fn sem_post 55ab165955SPhilippe Charnierfunction is signal-reentrant and may be called within signal handlers. 56b0a1b4f8SJason Evans.Sh RETURN VALUES 57b1250632SYaroslav Tykhiy.Rv -std sem_post 58b0a1b4f8SJason Evans.Sh ERRORS 59ab165955SPhilippe CharnierThe 60b0a1b4f8SJason Evans.Fn sem_post 61ab165955SPhilippe Charnierfunction will fail if: 62b0a1b4f8SJason Evans.Bl -tag -width Er 63b0a1b4f8SJason Evans.It Bq Er EINVAL 6426b6c45aSRuslan ErmilovThe 65b0a1b4f8SJason Evans.Fa sem 6626b6c45aSRuslan Ermilovargument 67b0a1b4f8SJason Evanspoints to an invalid semaphore. 68*49ba8a68SJilles Tjoelker.It Bq Er EOVERFLOW 69*49ba8a68SJilles TjoelkerThe semaphore value would exceed 70*49ba8a68SJilles Tjoelker.Dv SEM_VALUE_MAX . 71b0a1b4f8SJason Evans.El 72b0a1b4f8SJason Evans.Sh SEE ALSO 737a6d1e6fSRobert Watson.Xr sem_getvalue 3 , 7482db3da3SJason Evans.Xr sem_trywait 3 , 7515096da3SJohn Baldwin.Xr sem_wait 3 76b0a1b4f8SJason Evans.Sh STANDARDS 77ab165955SPhilippe CharnierThe 78b0a1b4f8SJason Evans.Fn sem_post 79ab165955SPhilippe Charnierfunction conforms to 80096841ecSRuslan Ermilov.St -p1003.1-96 . 81