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Diffstat (limited to 'lib/libc_r/man/sem_wait.3')
-rw-r--r-- | lib/libc_r/man/sem_wait.3 | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/lib/libc_r/man/sem_wait.3 b/lib/libc_r/man/sem_wait.3 new file mode 100644 index 00000000000..7df51f07092 --- /dev/null +++ b/lib/libc_r/man/sem_wait.3 @@ -0,0 +1,87 @@ +.\" $OpenBSD: sem_wait.3,v 1.1 2002/01/28 19:24:03 fgsch Exp $ +.\" Copyright (C) 2000 Jason Evans <jasone@FreeBSD.org>. +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice(s), this list of conditions and the following disclaimer as +.\" the first lines of this file unmodified other than the possible +.\" addition of one or more copyright notices. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice(s), this list of conditions and the following disclaimer in +.\" the documentation and/or other materials provided with the +.\" distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY +.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR +.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE +.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR +.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF +.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR +.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, +.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE +.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, +.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +.\" +.\" $FreeBSD: src/lib/libc_r/man/sem_wait.3,v 1.8 2001/10/01 16:09:09 ru Exp $ +.Dd February 15, 2000 +.Dt SEM_WAIT 3 +.Os +.Sh NAME +.Nm sem_wait , +.Nm sem_trywait +.Nd decrement (lock) a semaphore +.\" .Sh LIBRARY +.\" .Lb libc_r +.Sh SYNOPSIS +.In semaphore.h +.Ft int +.Fn sem_wait "sem_t *sem" +.Ft int +.Fn sem_trywait "sem_t *sem" +.Sh DESCRIPTION +The +.Fn sem_wait +function decrements (locks) the semaphore pointed to by +.Fa sem , +but blocks if the value of +.Fa sem +is zero, until the value is non-zero and the value can be decremented. +.Pp +The +.Fn sem_trywait +function decrements (locks) the semaphore pointed to by +.Fa sem +only if the value is non-zero. Otherwise, the semaphore is not decremented and +an error is returned. +.Sh RETURN VALUES +.Rv -std +.Sh ERRORS +.Fn sem_wait +and +.Fn sem_trywait +will fail if: +.Bl -tag -width Er +.It Bq Er EINVAL +.Fa sem +points to an invalid semaphore. +.El +.Pp +Additionally, +.Fn sem_trywait +will fail if: +.Bl -tag -width Er +.It Bq Er EAGAIN +The semaphore value was zero, and thus could not be decremented. +.El +.Sh SEE ALSO +.Xr sem_post 3 +.Sh STANDARDS +.Fn sem_wait +and +.Fn sem_trywait +conform to +.St -p1003.1-96 . |