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.Dd June 8, 2000
.Dt SEM_UNLINK 2
.Os Darwin
.Sh NAME
.Nm sem_unlink
.Nd remove a named semaphore
.Sh SYNOPSIS
.Fd #include <semaphore.h>
.Ft int
.Fn sem_unlink "const char *name"
.Sh DESCRIPTION
The named semaphore named
.Fa name
is removed.  If the semaphore is in use by other processes, then
.Fa name
is immediately disassociated with the semaphore, but the semaphore
itself will not be removed until all references to it have been
closed.  Subsequent calls to
.Fn sem_open
using
.Fa name
will refer to or create a new semaphore named
.Fa name .
.Pp
If successful,
.Fn sem_unlink
will return 0.  Otherwise, -1 is returned and
.Va errno
is set, and the state of the semaphore is unchanged.
.Sh ERRORS
.Fn sem_unlink
succeeds unless:
.Bl -tag -width Er
.It Bq Er EACCES
Permission is denied to be remove the semaphore.
.It Bq Er ENAMETOOLONG
.Fa name
exceeded
.Dv PSEMNAMLEN
characters.
.It Bq Er ENOENT
The named semaphore does not exist.
.El
.Sh SEE ALSO
.Xr sem_close 2 ,
.Xr sem_open 2 ,
.Xr semctl 2 ,
.Xr semget 2 ,
.Xr semop 2
.Sh HISTORY
.Fn sem_unlink
is specified in the POSIX Realtime Extension (1003.1b-1993/1003.1i-1995).