'\" te
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.TH sem_unlink 3C "5 Feb 2008" "SunOS 5.11" "Standard C Library Functions"
.SH NAME
sem_unlink \- remove a named semaphore
.SH SYNOPSIS
.LP
.nf
#include <semaphore.h>

\fBint\fR \fBsem_unlink\fR(\fBconst char *\fR\fIname\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBsem_unlink()\fR function removes the semaphore named by the string
\fIname\fR. If the semaphore named by \fIname\fR is currently referenced by
other processes, then \fBsem_unlink()\fR has no effect on the state of the
semaphore.  If one or more processes have the semaphore open when
\fBsem_unlink()\fR is called, destruction of the semaphore is postponed until
all references to the semaphore have been destroyed by calls to
\fBsem_close\fR(3C), \fB_Exit\fR(2), or one of the \fBexec\fR functions (see
\fBexec\fR(2)) . Calls to \fBsem_open\fR(3C) to re-create or re-connect to the
semaphore refer to a new semaphore after  \fBsem_unlink()\fR is called.  The
\fBsem_unlink()\fR call does not block until all references have been
destroyed; it returns immediately.
.SH RETURN VALUES
.sp
.LP
Upon successful completion, \fBsem_unlink()\fR returns \fB0\fR. Otherwise, the
semaphore is not changed and the function returns a value of \fB\(mi1\fR and
sets \fBerrno\fR to indicate the error.
.SH ERRORS
.sp
.LP
The  \fBsem_unlink()\fR function will fail if:
.sp
.ne 2
.mk
.na
\fB\fBEACCES\fR \fR
.ad
.RS 17n
.rt  
Permission is denied to unlink the named semaphore.
.RE

.sp
.ne 2
.mk
.na
\fB\fBENAMETOOLONG\fR \fR
.ad
.RS 17n
.rt  
The length of \fIname\fR string exceeds \fIPATH_MAX\fR, or a pathname component
is longer than \fINAME_MAX\fR while \fB_POSIX_NO_TRUNC\fR is in effect.
.RE

.sp
.ne 2
.mk
.na
\fB\fBENOENT\fR \fR
.ad
.RS 17n
.rt  
The named semaphore does not exist.
.RE

.sp
.ne 2
.mk
.na
\fB\fBENOSYS\fR \fR
.ad
.RS 17n
.rt  
The \fBsem_unlink()\fR function is not supported by the system.
.RE

.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
tab() box;
lw(2.75i) |lw(2.75i) 
lw(2.75i) |lw(2.75i) 
.
\fBATTRIBUTE TYPE\fR\fBATTRIBUTE VALUE\fR
_
Interface StabilityCommitted
_
MT-LevelMT-Safe
_
StandardSee \fBstandards\fR(5).
.TE

.SH SEE ALSO
.sp
.LP
\fBexec\fR(2), \fBexit\fR(2), \fBsem_close\fR(3C), \fBsem_open\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.