pthread_rwlock_unlock()
QNX SDP8.0C Library ReferenceAPIDeveloper
Unlock a read-write lock
Synopsis:
#include <pthread.h>
int pthread_rwlock_unlock( pthread_rwlock_t* rwl );
Arguments:
- rwl
- A pointer to a pthread_rwlock_t object that you want to unlock.
Library:
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
Description:
The pthread_rwlock_unlock() function unlocks a read-write lock referenced by rwl. The read-write lock may become available for any threads that were blocked on the lock, depending on whether it had been locked in exclusive or shared mode.
Note:
The read-write lock should be owned by the calling thread. If the
calling thread doesn't hold the lock, no error status is returned, and
the behavior of this read-write lock is now undefined.
Returns:
- EOK
- Success.
- EAGAIN
- On the first use of a statically initialized read-write lock, insufficient system resources existed to initialize it.
- EFAULT
- A fault occurred when the kernel tried to access rwl.
- EINVAL
- The read-write lock rwl is invalid.
- EPERM
- The calling thread doesn't have a write lock on rwl.
Examples:
See
An example of synchronization
in the Processes and Threads
chapter of Getting Started with the QNX OS.
Classification:
| Safety: | |
|---|---|
| Cancellation point | No |
| Signal handler | Yes |
| Thread | Yes |
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