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Diffstat (limited to 'lib/libpthread/man/pthread_rwlock_wrlock.3')
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diff --git a/lib/libpthread/man/pthread_rwlock_wrlock.3 b/lib/libpthread/man/pthread_rwlock_wrlock.3 new file mode 100644 index 00000000000..881e00c856d --- /dev/null +++ b/lib/libpthread/man/pthread_rwlock_wrlock.3 @@ -0,0 +1,103 @@ +.\" Copyright (c) 1998 Alex Nash +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" $Id: pthread_rwlock_wrlock.3,v 1.1 1998/11/09 03:13:16 d Exp $ +.\" $OpenBSD: pthread_rwlock_wrlock.3,v 1.1 1998/11/09 03:13:16 d Exp $ +.\" +.Dd August 4, 1998 +.Dt PTHREAD_RWLOCK_WRLOCK 3 +.Os +.Sh NAME +.Nm pthread_rwlock_wrlock , +.Nm pthread_rwlock_trywrlock +.Nd acquire a read/write lock for writing +.Sh SYNOPSIS +.Fd #include <pthread.h> +.Ft int +.Fn pthread_rwlock_wrlock "pthread_rwlock_t *lock" +.Ft int +.Fn pthread_rwlock_trywrlock "pthread_rwlock_t *lock" +.Sh DESCRIPTION +The +.Fn pthread_rwlock_wrlock +function blocks until a write lock can be acquired against +.Fa lock . +The +.Fn pthread_rwlock_trywrlock +function performs the same action, but does not block if the lock +cannot be immediately obtained. +.Pp +The results are undefined if the calling thread already holds the +lock at the time the call is made. +.Sh IMPLEMENTATION NOTES +To prevent writer starvation, writers are favored over readers. +.Sh RETURN VALUES +If successful, the +.Fn pthread_rwlock_wrlock +and +.Fn pthread_rwlock_trywrlock +functions will return zero. Otherwise an error number will be returned +to indicate the error. +.Sh SEE ALSO +.Xr pthread_rwlock_trywrlock 3 , +.Xr pthread_rwlock_unlock 3 , +.Xr pthread_rwlock_wrlock 3 +.Sh STANDARDS +The +.Fn pthread_rwlock_wrlock +and +.Fn pthread_rwlock_trywrlock +functions are expected to conform to +.St -susv2 . +.Sh ERRORS +The +.Fn pthread_rwlock_trywrlock +function will fail if: +.Bl -tag -width Er +.It Bq Er EBUSY +The calling thread is not able to acquire the lock without blocking. +.El +.Pp +The +.Fn pthread_rwlock_wrlock +and +.Fn pthread_rwlock_trywrlock +functions may fail if: +.Bl -tag -width Er +.It Bq Er EDEADLK +The calling thread already owns the read/write lock (for reading +or writing). +.It Bq Er EINVAL +The value specified by +.Fa lock +is invalid. +.It Bq Er ENOMEM +Insufficient memory exists to initialize the lock (applies to +statically initialized locks only). +.El +.Sh HISTORY +The +.Fn pthread_rwlock_wrlock +function first appeared in +.Fx 3.0 . |