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1.\" $OpenBSD: sem_destroy.3,v 1.8 2025/06/07 00:16:52 schwarze Exp $
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30.\" $FreeBSD: src/lib/libc_r/man/sem_destroy.3,v 1.9 2001/10/01 16:09:09 ru Exp $
31.Dd $Mdocdate: June 7 2025 $
32.Dt SEM_DESTROY 3
33.Os
34.Sh NAME
35.Nm sem_destroy
36.Nd destroy an unnamed semaphore
37.Sh SYNOPSIS
38.Lb libpthread
39.In semaphore.h
40.Ft int
41.Fn sem_destroy "sem_t *sem"
42.Sh DESCRIPTION
43The
44.Fn sem_destroy
45function destroys the unnamed semaphore pointed to by
46.Fa sem .
47After a successful call to
48.Fn sem_destroy ,
49.Fa sem
50is unusable until re-initialized by another call to
51.Xr sem_init 3 .
52.Sh RETURN VALUES
53.Rv -std sem_destroy
54.Sh ERRORS
55.Fn sem_destroy
56will fail if:
57.Bl -tag -width Er
58.It Bq Er EINVAL
59.Fa sem
60points to an invalid semaphore.
61.It Bq Er EBUSY
62There are currently threads blocked on the semaphore that
63.Fa sem
64points to.
65.El
66.Sh SEE ALSO
67.Xr sem_getvalue 3 ,
68.Xr sem_init 3 ,
69.Xr sem_open 3 ,
70.Xr sem_post 3 ,
71.Xr sem_wait 3
72.Sh STANDARDS
73.Fn sem_destroy
74conforms to
75.St -p1003.1-96 .
76.Pp
77POSIX does not define the behavior of
78.Fn sem_destroy
79if called while there are threads blocked on
80.Fa sem ,
81but this implementation is guaranteed to return -1 and set
82.Va errno
83to
84.Er EBUSY
85if there are threads blocked on
86.Fa sem .