29        not acquired, the calling thread blocks until it can acquire the lock.
  30 
  31 
  32        A thread can hold multiple concurrent read locks on rwlock (that is,
  33        successfully call the pthread_rwlock_rdlock() function n times). If so,
  34        the thread must perform matching unlocks (that is, it must call the
  35        pthread_rwlock_unlock() function n times).
  36 
  37 
  38        The maximum number of concurrent read locks that a thread can hold on
  39        one read-write lock is currently set at 100,000, though this number
  40        could change in a future release. There is no imposed limit on the
  41        number of different threads that can apply a read lock to one read-
  42        write lock.
  43 
  44 
  45        The pthread_rwlock_tryrdlock() function applies a read lock like the
  46        pthread_rwlock_rdlock() function, with the exception that the function
  47        fails if the equivalent pthread_rwlock_rdlock() call would have blocked
  48        the calling thread.  In no case will the pthread_rwlock_tryrdlock()
  49        function ever bloc. It always either acquires the lock or fails and
  50        returns immediately.
  51 
  52 
  53        Results are undefined if any of these functions are called with an
  54        uninitialized read-write lock.
  55 
  56 
  57        If a signal is delivered to a thread waiting for a read-write lock for
  58        reading, upon return from the signal handler the thread resumes waiting
  59        for the read-write lock for reading as if it was not interrupted.
  60 
  61 RETURN VALUES
  62        If successful, the pthread_rwlock_rdlock() function returns 0.
  63        Otherwise, an error number is returned to indicate the error.
  64 
  65 
  66        The pthread_rwlock_tryrdlock() function returns 0 if the lock for
  67        reading on the read-write lock object referenced by rwlock is acquired.
  68        Otherwise an error number  is returned to indicate the error.
  69 

  29        not acquired, the calling thread blocks until it can acquire the lock.
  30 
  31 
  32        A thread can hold multiple concurrent read locks on rwlock (that is,
  33        successfully call the pthread_rwlock_rdlock() function n times). If so,
  34        the thread must perform matching unlocks (that is, it must call the
  35        pthread_rwlock_unlock() function n times).
  36 
  37 
  38        The maximum number of concurrent read locks that a thread can hold on
  39        one read-write lock is currently set at 100,000, though this number
  40        could change in a future release. There is no imposed limit on the
  41        number of different threads that can apply a read lock to one read-
  42        write lock.
  43 
  44 
  45        The pthread_rwlock_tryrdlock() function applies a read lock like the
  46        pthread_rwlock_rdlock() function, with the exception that the function
  47        fails if the equivalent pthread_rwlock_rdlock() call would have blocked
  48        the calling thread.  In no case will the pthread_rwlock_tryrdlock()
  49        function ever block. It always either acquires the lock or fails and
  50        returns immediately.
  51 
  52 
  53        Results are undefined if any of these functions are called with an
  54        uninitialized read-write lock.
  55 
  56 
  57        If a signal is delivered to a thread waiting for a read-write lock for
  58        reading, upon return from the signal handler the thread resumes waiting
  59        for the read-write lock for reading as if it was not interrupted.
  60 
  61 RETURN VALUES
  62        If successful, the pthread_rwlock_rdlock() function returns 0.
  63        Otherwise, an error number is returned to indicate the error.
  64 
  65 
  66        The pthread_rwlock_tryrdlock() function returns 0 if the lock for
  67        reading on the read-write lock object referenced by rwlock is acquired.
  68        Otherwise an error number  is returned to indicate the error.
  69