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pthread_rwlock_unlock(3)
NAME
  pthread_rwlock_unlock - Unlock a read-write lock

SYNOPSIS
  #include <pthread.h>

  int pthread_rwlock_unlock(
	  pthread_rwlock_t *rwlock );

LIBRARY
  DECthreads POSIX 1003.1c Library (libpthread.so)

PARAMETERS
  rwlock
      Address of the read-write lock to be unlocked.

DESCRIPTION
  This routine releases a lock acquisition held on the read-write lock object
  referenced by rwlock. Results are undefined if rwlock is not held by the
  calling thread.

  If this routine is called to release a lock for read access on rwlock and
  the calling thread also currently holds other locks for read access on
  rwlock, the read-write lock object remains in the read locked state. If
  this routine releases the calling thread's last lock for read access on
  rwlock, the calling thread is not longer one of the owners of the lock
  object.

  If this routine is called to release a lock for write access on rwlock, the
  lock object is put in the unlocked state with no owners.

  If a call to this routine results in the read-write lock object becoming
  unlocked and there are multiple thread waiting to acquire that lock for
  write access, DECthreads uses the scheduling policy of those waiting
  threads to determine which thread next acquires the lock object for write
  access. If there are multiple thread waiting to acquire the read-write lock
  object for read access, DECthreads uses the scheduling policy of those
  waiting threads to determine the order in which those threads acquire the
  lock for read access.	 If there are multiple threads waiting to acquire the
  read-write lock object for both read and write access, it is unspecified
  whether a thread waiting for read access or for write access next acquires
  the lock object.

  If the read-write lock object referenced by rwlock is not initialized, the
  results of calling this routine are undefined.

RETURN VALUES
  If an error condition occurs, this routine returns an integer value
  indicating the type of error. Possible return values are as follows:

  0   Successful completion.

  [EINVAL]
      The values specified by rwlock does not refer to an initialized read-
      write lock object.

  [EPERM]
      The current thread does not hold the read-write lock object.

ERRORS
  None

SEE ALSO
  Functions: pthread_rwlock_init(3), pthread_rwlock_rdlock(3),
  pthread_rwlock_wrlock(3), pthread_rwlockattr_init(3)

  Manuals: Guide to DECthreads and Programmer's Guide

Index for Section 3

Alphabetical listing for P

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