Standard C Library Functions            pthreadrwlockwrlock(3C)



NAME
     pthreadrwlockwrlock, pthreadrwlocktrywrlock  -  lock  or
     attempt to lock read-write lock object for writing

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

     int pthreadrwlockwrlock(pthreadrwlockt *rwlock);


     int pthreadrwlocktrywrlock(pthreadrwlockt *rwlock);


DESCRIPTION
     The pthreadrwlockwrlock() function applies a write lock to
     the read-write lock referenced by rwlock. The calling thread
     acquires the write  lock  if  no  other  thread  (reader  or
     writer)  holds  the  read-write  lock rwlock. Otherwise, the
     thread blocks until it can acquire the lock.


     The pthreadrwlocktrywrlock() function applies a write lock
     like  the  pthreadrwlockwrlock() function, with the excep-
     tion that the function fails if any thread  currently  holds
     rwlock (for reading or writing).


     Writers are favored over readers of  the  same  priority  to
     avoid writer starvation. See pthreadrwlockrdlock(3C).


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


     If a signal is delivered to a thread  waiting  for  a  read-
     write  lock for writing, upon return from the signal handler
     the thread resumes waiting for the read-write lock for writ-
     ing as if it was not interrupted.

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


     The pthreadrwlocktrywrlock() function  returns  0  if  the
     lock for writing on the read-write lock object referenced by
     rwlock is acquired.  Otherwise an error number  is  returned
     to indicate the error.




SunOS 5.11          Last change: 23 Mar 2005                    1






Standard C Library Functions            pthreadrwlockwrlock(3C)



ERORS
     The pthreadrwlockwrlock() function will fail if:

     EDEADLK    The current thread already  owns  the  read-write
                lock for writing or reading.



     The pthreadrwlocktrywrlock() function will fail if:

     EBUSY    The read-write lock could not be acquired for writ-
              ing  because  it  was already locked for reading or
              writing.


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



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface Stability          Standard                    
    
     MT-Level                     MT-Safe                     
    


SEE ALSO
     pthreadrwlockinit(3C),          pthreadrwlockunlock(3C),
     pthreadrwlockattrinit(3C),      pthreadrwlockrdlock(3C),
     attributes(5), standards(5)





















SunOS 5.11          Last change: 23 Mar 2005                    2