Manual Pages  — PTHREAD_RWLOCK_INIT

pthread_rwlock_init – initialize a read/write lock

LIBRARY SYNOPSIS DESCRIPTION RETURN VALUES ERRORS SEE ALSO STANDARDS HISTORY

POSIX Threads Library (libpthread, -lpthread)

#include <pthread.h>

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

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.

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

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.

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

The pthread_rwlock_init() function first appeared in FreeBSD 3.0 .