Manual Pages for UNIX Operating System command usage for man pthread_rwlock_unlock

Standard C Library Functions            pthread_rwlock_unlock(3C)



NAME
     pthread_rwlock_unlock - unlock read-write lock object

SYNOPSIS
     cc -mt [ flag... ] file... -lpthread [ library... ]
     #include 

     int pthread_rwlock_unlock(pthread_rwlock_t *rwlock);


DESCRIPTION
     The pthread_rwlock_unlock() function is called to release  a
     lock  held  on  the  read-write  lock  object  referenced by
     rwlock. Results are undefined if the read-write lock  rwlock
     is not held by the calling thread.


     If this function is called to release a read lock  from  the
     read-write  lock  object  and  there  are  other  read locks
     currently held on this read-write  lock  object,  the  read-
     write  lock object remains in the read locked state. If this
     function releases the calling thread's  last  read  lock  on
     this  read-write  lock object, then the calling thread is no
     longer one of the owners of the  object.  If  this  function
     releases the last read lock for this read-write lock object,
     the read-write lock object will be put in the unlocked state
     with no owners.


     If this function is called to release a write lock for  this
     read-write  lock  object, the read-write lock object will be
     put in the unlocked state with no owners.


     If the call to the pthread_rwlock_unlock() function  results
     in  the  read-write  lock object becoming unlocked and there
     are multiple threads waiting to acquire the read-write  lock
     object  for writing, the scheduling policy is used to deter-
     mine which thread acquires the read-write  lock  object  for
     writing.  If  there  are multiple threads waiting to acquire
     the read-write lock object for reading, the scheduling  pol-
     icy  is  used  to  determine  the order in which the waiting
     threads acquire the read-write lock object for reading.   If
     there  are  multiple threads blocked on rwlock for both read
     locks and write locks, it is unspecified whether the readers
     acquire the lock first or whether a writer acquires the lock
     first.


     Results are undefined if any of these functions  are  called
     with an uninitialized read-write lock.




SunOS 5.11          Last change: 23 Mar 2005                    1






Standard C Library Functions            pthread_rwlock_unlock(3C)



RETURN VALUES
     If successful, the pthread_rwlock_unlock() function  returns
     0.  Otherwise,  an  error number is returned to indicate the
     error.

ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|
    | Standard                    | See standards(5).           |
    |_____________________________|_____________________________|


SEE ALSO
     pthread_rwlock_init(3C),          pthread_rwlock_rdlock(3C),
     pthread_rwlock_wrlock(3C),      pthread_rwlockattr_init(3C),
     attributes(5), standards(5)





























SunOS 5.11          Last change: 23 Mar 2005                    2