NAME    [Toc]    [Back]

     pthread_rwlock_init - initialize a read/write lock

SYNOPSIS    [Toc]    [Back]

     #include <pthread.h>

     int
     pthread_rwlock_init(pthread_rwlock_t *lock,
             const pthread_rwlockattr_t *attr);

DESCRIPTION    [Toc]    [Back]

     The pthread_rwlock_init() function is used to  initialize  a
read/write
     lock,  with  attributes specified by attr.  If attr is NULL,
the default
     read/write lock attributes are used.

     The results of calling pthread_rwlock_init() with an already
initialized
     lock are undefined.

RETURN VALUES    [Toc]    [Back]

     If  successful,  the pthread_rwlock_init() function will return zero.  Otherwise
 an error number will be returned to indicate the  error.

ERRORS    [Toc]    [Back]

     The pthread_rwlock_init() function will fail if:

     [EAGAIN]       The  system  lacked  the  necessary resources
(other than memory)
 to initialize the lock.

     [ENOMEM]      Insufficient memory exists to  initialize  the
lock.

     [EPERM]        The caller does not have sufficient privilege
to perform
                   the operation.

     The pthread_rwlock_init() function may fail if:

     [EBUSY]       The system has detected an attempt to  re-initialize the object
 referenced by lock, a previously initialized but not
                   yet destroyed read/write lock.

     [EINVAL]      The value specified by attr is invalid.

SEE ALSO    [Toc]    [Back]

     pthread_rwlock_destroy(3), pthread_rwlockattr_init(3),
     pthread_rwlockattr_setpshared(3)

STANDARDS    [Toc]    [Back]

     The pthread_rwlock_init() function is expected to conform to
Version 2 of
     the Single UNIX Specification.

HISTORY    [Toc]    [Back]

     The pthread_rwlock_init() function first appeared in FreeBSD
3.0 and
     OpenBSD 2.5.

BUGS    [Toc]    [Back]

     The PTHREAD_PROCESS_SHARED attribute is not supported.

OpenBSD     3.6                          August      4,      1998