Manual Pages for UNIX Operating System command usage for man pthread_rwlock_timedrdlock

Standard C Library Functions       pthread_rwlock_timedrdlock(3C)



NAME
     pthread_rwlock_timedrdlock, pthread_rwlock_reltimedrdlock_np
     - lock a read-write lock for reading

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

     int pthread_rwlock_timedrdlock(pthread_rwlock_t *restrict rwlock,
          const struct timespec *restrict abs_timeout);


     int pthread_rwlock_reltimedrdlock_np(pthread_rwlock_t *restrict rwlock,
          const struct timespec *restrict rel_timeout);


DESCRIPTION
     The pthread_rwlock_timedrdlock()  function  applies  a  read
     lock  to  the read-write lock referenced by rwlock as in the
     pthread_rwlock_rdlock(3C) function. If the  lock  cannot  be
     acquired  without  waiting  for  other threads to unlock the
     lock, this  wait  will  be  terminated  when  the  specified
     timeout  expires. The timeout expires when the absolute time
     specified  by  abs_timeout  passes,  as  measured   by   the
     CLOCK_REALTIME  clock (that is, when the value of that clock
     equals or exceeds abs_timeout),  or  if  the  absolute  time
     specified by abs_timeout has already been passed at the time
     of the call.


     The pthread_rwlock_reltimedrdlock_np() function is identical
     to  the  pthread_rwlock_timedrdlock()  function, except that
     the timeout is specified as a relative time  interval.   The
     timeout   expires   when  the  time  interval  specified  by
     rel_timeout passes, as measured by the CLOCK_REALTIME clock,
     or if the time interval specified by rel_timeout is negative
     at the time of the call.


     The resolution of the  timeout  is  the  resolution  of  the
     CLOCK_REALTIME  clock.  The timespec data type is defined in
     the  header.  Under  no  circumstances  does  either
     function  fail  with  a  timeout if the lock can be acquired
     immediately. The validity of the timeout parameter need  not
     be checked if the lock can be immediately acquired.


     If a signal that causes a signal handler to be  executed  is
     delivered  to  a  thread blocked on a read-write lock with a
     call        to        pthread_rwlock_timedrdlock()        or
     pthread_rwlock_reltimedrdlock_np(),  upon  return  from  the



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Standard C Library Functions       pthread_rwlock_timedrdlock(3C)



     signal handler the thread resumes waiting for the lock as if
     it was not interrupted.


     The calling thread might deadlock if at the time the call is
     made it holds a write lock on rwlock.


     The results are undefined if this function is called with an
     uninitialized read-write lock.

RETURN VALUES
     The             pthread_rwlock_timedrdlock()             and
     pthread_rwlock_reltimedrdlock_np() functions return 0 if the
     lock for reading on the read-write lock object referenced by
     rwlock  is  acquired. Otherwise, an error number is returned
     to indicate the error.

ERRORS
     The       pthread_rwlock_timedrdlock()        and        and
     pthread_rwlock_reltimedrdlock_np() functions will fail if:

     ETIMEDOUT     The lock could  not  be  acquired  before  the
                  specified timeout expired.



     The             pthread_rwlock_timedrdlock()             and
     pthread_rwlock_reltimedrdlock_np() functions may fail if:

     EAGAIN     The read lock could not be acquired  because  the
                maximum  number  of  read locks for lock would be
                exceeded.


     EDEADLK    The calling thread already holds a write lock  on
                rwlock.


     EINVAL     The value specified by rwlock does not  refer  to
                an  initialized  read-write  lock  object, or the
                timeout nanosecond value is  less  than  zero  or
                greater than or equal to 1 000 million.


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







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Standard C Library Functions       pthread_rwlock_timedrdlock(3C)



     _____________________________________________________________
   |        ATTRIBUTE TYPE       |         ATTRIBUTE VALUE      |
   | ____________________________|______________________________|_
   |  Interface Stability        |  Committed                   |
   | ____________________________|______________________________|_
   |  MT-Level                   |  MT-Safe                     |
   | ____________________________|______________________________|_
   |  Standard                   |  For                         |
   |                             |  pthread_rwlock_timedrdlock(),|
   |                             |  see standards(5).           |
   |_____________________________|______________________________|


SEE ALSO
     pthread_rwlock_destroy(3C),       pthread_rwlock_rdlock(3C),
     pthread_rwlock_timedwrlock(3C),
     pthread_rwlock_trywrlock(3C),     pthread_rwlock_unlock(3C),
     pthread_rwlock_wrlock(3C), attributes(5), standards(5)





































SunOS 5.11          Last change: 30 Jan 2004                    3