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.

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.