pthread_rwlock_wrlockpthread_rwlock_trywrlock
- acquire a read/write lock for writing
LIBRARY
Lb libpthread
SYNOPSIS
#include <pthread.h> int
pthread_rwlock_wrlock (pthread_rwlock_t *lock); int
pthread_rwlock_trywrlock (pthread_rwlock_t *lock);
DESCRIPTION
The
pthread_rwlock_wrlock ();
function blocks until a write lock can be acquired against
Fa lock .
The
pthread_rwlock_trywrlock ();
function performs the same action, but does not block if the lock
cannot be immediately obtained.
The results are undefined if the calling thread already holds the
lock at the time the call is made.
IMPLEMENTATION NOTES
To prevent writer starvation, writers are favored over readers.
RETURN VALUES
If successful, the
pthread_rwlock_wrlock ();
and
pthread_rwlock_trywrlock ();
functions will return zero.
Otherwise an error number will be returned
to indicate the error.
ERRORS
The
pthread_rwlock_trywrlock ();
function will fail if:
Bq Er EBUSY
The calling thread is not able to acquire the lock without blocking.
The
pthread_rwlock_wrlock ();
and
pthread_rwlock_trywrlock ();
functions may fail if:
Bq Er EDEADLK
The calling thread already owns the read/write lock (for reading
or writing).
Bq Er EINVAL
The value specified by
Fa lock
is invalid.
Bq Er ENOMEM
Insufficient memory exists to initialize the lock (applies to
statically initialized locks only).
