xref: /freebsd/share/man/man3/pthread_rwlock_init.3 (revision ae83180158c4c937f170e31eff311b18c0286a93)
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25.\" $FreeBSD$
26.\"
27.Dd August 4, 1998
28.Dt PTHREAD_RWLOCK_INIT 3
29.Os
30.Sh NAME
31.Nm pthread_rwlock_init
32.Nd initialize a read/write lock
33.Sh LIBRARY
34.Lb libc_r
35.Sh SYNOPSIS
36.In pthread.h
37.Ft int
38.Fn pthread_rwlock_init "pthread_rwlock_t *lock" "const pthread_rwlockattr_t *attr"
39.Sh DESCRIPTION
40The
41.Fn pthread_rwlock_init
42function is used to initialize a read/write lock, with attributes
43specified by
44.Fa attr .
45If
46.Fa attr
47is NULL, the default read/write lock attributes are used.
48.Pp
49The results of calling
50.Fn pthread_rwlock_init
51with an already initialized lock are undefined.
52.Sh RETURN VALUES
53If successful, the
54.Fn pthread_rwlock_init
55function will return zero.  Otherwise an error number will be returned
56to indicate the error.
57.Sh SEE ALSO
58.Xr pthread_rwlockattr_init 3 ,
59.Xr pthread_rwlockattr_setpshared 3 ,
60.Xr pthread_rwlock_destroy 3
61.Sh STANDARDS
62The
63.Fn pthread_rwlock_init
64function is expected to conform to
65.St -susv2 .
66.Sh ERRORS
67The
68.Fn pthread_rwlock_init
69function will fail if:
70.Bl -tag -width Er
71.It Bq Er EAGAIN
72The system lacked the necessary resources (other than memory) to
73initialize the lock.
74.It Bq Er ENOMEM
75Insufficient memory exists to initialize the lock.
76.It Bq Er EPERM
77The caller does not have sufficient privilege to perform the
78operation.
79.El
80.Pp
81The
82.Fn pthread_rwlock_init
83function may fail if:
84.Bl -tag -width Er
85.It Bq Er EBUSY
86The system has detected an attempt to re-initialize the object
87referenced by
88.Fa lock ,
89a previously initialized but not yet destroyed read/write lock.
90.It Bq Er EINVAL
91The value specified by
92.Fa attr
93is invalid.
94.El
95.Sh HISTORY
96The
97.Fn pthread_rwlock_init
98function first appeared in
99.Fx 3.0 .
100.Sh BUGS
101The PTHREAD_PROCESS_SHARED attribute is not supported.
102