posix_lock_file(9) [suse man page]

POSIX_LOCK_FILE(9)						   The Linux VFS						POSIX_LOCK_FILE(9)

NAME

       posix_lock_file - Apply a POSIX-style lock to a file

SYNOPSIS

       int posix_lock_file(struct file * filp, struct file_lock * fl, struct file_lock * conflock);

ARGUMENTS

       filp
	   The file to apply the lock to

       fl
	   The lock to be applied

       conflock
	   Place to return a copy of the conflicting lock, if found.

DESCRIPTION

       Add a POSIX style lock to a file. We merge adjacent & overlapping locks whenever possible. POSIX locks are sorted by owner task, then by
       starting address

       Note that if called with an FL_EXISTS argument, the caller may determine whether or not a lock was successfully freed by testing the return
       value for -ENOENT.

COPYRIGHT

Kernel Hackers Manual 2.6.					     July 2010							POSIX_LOCK_FILE(9)

pthread_rwlock_unlock(3T)												 pthread_rwlock_unlock(3T)

NAME

       pthread_rwlock_unlock() - unlock a read-write lock.

SYNOPSIS

PARAMETERS

	      rwlock	Pointer to the read-write lock to be unlocked.

DESCRIPTION

       The  function  is  called  by  the owner to release the read-write lock 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 on the read-write lock rwlock and there are other read locks currently held on this read-
       write lock, the read-write lock shall remain in the read locked state but without the current thread as one of its owners. If this function
       releases the last read lock for this read-write lock, the object shall be put in the unlocked state with no owners.

       If this function is called to release a write lock on the read-write lock rwlock, the read-write lock shall be put in  the  unlocked  state
       with no owners.

       If  the	call to the function results in the read-write lock becoming unlocked and there are threads waiting to acquire the read-write lock
       for writing, the scheduling policy is used to determine which thread shall acquire the read-write lock for writing. If  there  are  threads
       waiting	to  acquire  the  read-write  lock  object  for reading, the scheduling policy is used to determine the order in which the waiting
       threads shall 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 will acquire the lock first or whether a writer will acquire the lock first.

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

RETURN VALUE

       Upon successful completion, returns zero. Otherwise, an error number is returned to indicate the error (the variable is not set).

ERRORS

       For each of the following conditions, if the condition is detected, the function returns the corresponding error number:

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

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

AUTHOR

       was developed by X/Open.

SEE ALSO

       pthread_rwlock_init(3T),  pthread_rwlock_destroy(3T),  pthread_rwlock_rdlock(3T),  pthread_rwlock_wrlock(3T), pthread_rwlock_tryrdlock(3T),
       pthread_rwlock_trywrlock(3T).

STANDARDS CONFORMANCE

								  Pthread Library					 pthread_rwlock_unlock(3T)