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Diffstat (limited to 'lib/libc/gen/sem_init.3')
-rw-r--r-- | lib/libc/gen/sem_init.3 | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/lib/libc/gen/sem_init.3 b/lib/libc/gen/sem_init.3 new file mode 100644 index 0000000..d765a57 --- /dev/null +++ b/lib/libc/gen/sem_init.3 @@ -0,0 +1,108 @@ +.\" 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. +.\" +.\" $FreeBSD$ +.\" +.Dd February 15, 2000 +.Dt SEM_INIT 3 +.Os +.Sh NAME +.Nm sem_init +.Nd initialize an unnamed semaphore +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In semaphore.h +.Ft int +.Fn sem_init "sem_t *sem" "int pshared" "unsigned int value" +.Sh DESCRIPTION +The +.Fn sem_init +function initializes the unnamed semaphore pointed to by +.Fa sem +to have the value +.Fa value . +A non-zero value for +.Fa pshared +specifies a shared semaphore that can be used by multiple processes, which this +implementation is not capable of. +.Pp +Following a successful call to +.Fn sem_init , +.Fa sem +can be used as an argument in subsequent calls to +.Xr sem_wait 3 , +.Xr sem_trywait 3 , +.Xr sem_post 3 , +and +.Xr sem_destroy 3 . +The +.Fa sem +argument is no longer valid after a successful call to +.Xr sem_destroy 3 . +.Sh RETURN VALUES +.Rv -std sem_init +.Sh ERRORS +The +.Fn sem_init +function will fail if: +.Bl -tag -width Er +.It Bq Er EINVAL +The +.Fa value +argument exceeds +.Dv SEM_VALUE_MAX . +.It Bq Er ENOSPC +Memory allocation error. +.It Bq Er EPERM +Unable to initialize a shared semaphore. +.El +.Sh SEE ALSO +.Xr sem_destroy 3 , +.Xr sem_getvalue 3 , +.Xr sem_post 3 , +.Xr sem_trywait 3 , +.Xr sem_wait 3 , +.Xr sem 4 +.Sh STANDARDS +The +.Fn sem_init +function conforms to +.St -p1003.1-96 . +.Pp +This implementation does not support shared semaphores, and reports this fact +by setting +.Va errno +to +.Er EPERM . +This is perhaps a stretch of the intention of +.Tn POSIX , +but is +compliant, with the caveat that +.Fn sem_init +always reports a permissions error when an attempt to create a shared semaphore +is made. |