PTHREAD_RWLOCK_INIT(3)                        FreeBSD Library Functions Manual

NAME
     pthread_rwlock_init - initialize a read/write lock

LIBRARY
     POSIX Threads Library (libpthread, -lpthread)

SYNOPSIS
     #include <pthread.h>

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

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

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

STANDARDS
     The pthread_rwlock_init() function is expected to conform to Version 2 of
     the Single UNIX Specification ("SUSv2").

HISTORY
     The pthread_rwlock_init() function first appeared in FreeBSD 3.0.

FreeBSD 13.1-RELEASE-p6         August 17, 2018        FreeBSD 13.1-RELEASE-p6