projects / apple / libc.git / blame
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|---|---|---|
| e9ce8d39 A |
1 | .\" $Darwin$ |
| 2 | .\" | |
| 5b2abdfb | 3 | .\" Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved. |
| e9ce8d39 A |
4 | .\" |
| 5 | .\" @APPLE_LICENSE_HEADER_START@ | |
| 6 | .\" | |
| 7 | .\" The contents of this file constitute Original Code as defined in and | |
| 8 | .\" are subject to the Apple Public Source License Version 1.1 (the | |
| 9 | .\" "License"). You may not use this file except in compliance with the | |
| 10 | .\" License. Please obtain a copy of the License at | |
| 11 | .\" http://www.apple.com/publicsource and read it before using this file. | |
| 12 | .\" | |
| 13 | .\" This Original Code and all software distributed under the License are | |
| 14 | .\" distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER | |
| 15 | .\" EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, | |
| 16 | .\" INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, | |
| 17 | .\" FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the | |
| 18 | .\" License for the specific language governing rights and limitations | |
| 19 | .\" under the License. | |
| 20 | .\" | |
| 21 | .\" @APPLE_LICENSE_HEADER_END@ | |
| 22 | .\" | |
| 23 | .Dd June 8, 2000 | |
| 24 | .Dt SEM_POST 2 | |
| 25 | .Os Darwin | |
| 26 | .Sh NAME | |
| 27 | .Nm sem_post | |
| 28 | .Nd unlock a semaphore | |
| 29 | .Sh SYNOPSIS | |
| 30 | .Fd #include <semaphore.h> | |
| 31 | .Ft int | |
| 32 | .Fn sem_post "sem_t *sem" | |
| 33 | .Sh DESCRIPTION | |
| 34 | The the semaphore referenced by | |
| 35 | .Fa sem | |
| 36 | is unlocked, the value of the semaphore is incremented, and all | |
| 37 | threads which are waiting on the semaphore are awakened. | |
| 38 | .Pp | |
| 39 | .Fn sem_post | |
| 40 | is reentrant with respect to signals and may be called from within a | |
| 41 | signal hanlder. | |
| 42 | .Pp | |
| 43 | If successful, | |
| 44 | .Fn sem_post | |
| 45 | will return 0. Otherwise, -1 is returned and | |
| 46 | .Va errno | |
| 47 | is set. | |
| 48 | .Sh ERRORS | |
| 49 | .Fn sem_post | |
| 50 | succeeds unless: | |
| 51 | .Bl -tag -width Er | |
| 52 | .It Bq Er EINVAL | |
| 53 | .Fa sem | |
| 54 | is not a valid semaphore descriptor. | |
| 55 | .El | |
| 56 | .Sh SEE ALSO | |
| 57 | .Xr semctl 2 , | |
| 58 | .Xr semget 2 , | |
| 59 | .Xr semop 2 , | |
| 60 | .Xr sem_open 2 , | |
| 61 | .Xr sem_trywait 2 , | |
| 62 | .Xr sem_wait 2 | |
| 63 | .Sh HISTORY | |
| 64 | .Fn sem_post | |
| 65 | is specified in the POSIX Realtime Extension (1003.1b-1993/1003.1i-1995). |