'\" te
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.TH SEM_CLOSE 3C "Feb 5, 2008"
.SH NAME
sem_close \- close a named semaphore
.SH SYNOPSIS
.LP
.nf
#include <semaphore.h>

\fBint\fR \fBsem_close\fR(\fBsem_t *\fR\fIsem\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBsem_close()\fR function is used to indicate that the calling process is
finished using the named semaphore indicated by \fIsem\fR. The effects of
calling \fBsem_close()\fR for an unnamed semaphore (one created by
\fBsem_init\fR(3C)) are undefined. The \fBsem_close()\fR function deallocates
(that is, make available for reuse by a subsequent \fBsem_open\fR(3C) by this
process) any system resources allocated by the system for use by this process
for this semaphore. The effect of subsequent use of the semaphore indicated by
\fIsem\fR by this process is undefined. If the semaphore has not been removed
with a successful call to \fBsem_unlink\fR(3C), then \fBsem_close()\fR has no
effect on the state of the semaphore. If the \fBsem_unlink\fR(3C) function has
been successfully invoked for \fIname\fR after the most recent call to
\fBsem_open\fR(3C) with \fBO_CREAT\fR for this semaphore, then when all
processes that have opened the semaphore close it, the semaphore is no longer
be accessible.
.SH RETURN VALUES
.sp
.LP
If successful, \fBsem_close()\fR returns \fB0\fR, otherwise it returns
\fB\(mi1\fR and sets \fBerrno\fR to indicate the error.
.SH ERRORS
.sp
.LP
The \fBsem_close()\fR function will fail if:
.sp
.ne 2
.na
\fB\fBEINVAL\fR \fR
.ad
.RS 11n
The \fIsem\fR argument is not a valid semaphore descriptor.
.RE

.sp
.ne 2
.na
\fB\fBENOSYS\fR \fR
.ad
.RS 11n
The \fBsem_close()\fR function is not supported by the system.
.RE

.SH USAGE
.sp
.LP
The \fBsem_close()\fR function should not be called for an unnamed semaphore
initialized by \fBsem_init\fR(3C).
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Committed
_
MT-Level	MT-Safe
_
Standard	See \fBstandards\fR(5).
.TE

.SH SEE ALSO
.sp
.LP
\fBsem_init\fR(3C), \fBsem_open\fR(3C), \fBsem_unlink\fR(3C),
\fBattributes\fR(5), \fBstandards\fR(5)
.SH NOTES
.sp
.LP
Solaris 2.6 was the first release to support the Asynchronous Input and Output
option. Prior to this release, this function always returned \fB\(mi1\fR and
set \fBerrno\fR to \fBENOSYS\fR.