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diff --git a/share/man/man3/pthread_rwlock_timedrdlock.3 b/share/man/man3/pthread_rwlock_timedrdlock.3 new file mode 100644 index 000000000000..78b74700ce75 --- /dev/null +++ b/share/man/man3/pthread_rwlock_timedrdlock.3 @@ -0,0 +1,118 @@ +.\" Copyright (c) 2004 Michael Telahun Makonnen +.\" 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. +.\" +.\" $FreeBSD$ +.\" +.Dd January 16, 2004 +.Dt PTHREAD_RWLOCK_TIMEDRDLOCK 3 +.Os +.Sh NAME +.Nm pthread_rwlock_timedrdlock +.Nd "acquire a read-write lock for reading or give up after a specified period" +.Sh LIBRARY +.Lb libpthread +.Sh SYNOPSIS +.In pthread.h +.Ft int +.Fn pthread_rwlock_timedrdlock "pthread_rwlock_t *rwlock" "const struct timespec *abs_timeout" +.Sh DESCRIPTION +This function acquires a read lock on the read-write lock +.Fa rwlock . +However, if the lock cannot be +acquired without waiting for another thread to +unlock the lock, +this wait shall be terminated when +.Fa abs_timeout +expires. +.Pp +A thread may hold multiple concurrent read locks. +The +.Xr pthread_rwlock_unlock 3 +function must be called once for each lock acquired. +.Pp +If the thread should be interrupted by a signal, +the +.Fn pthread_rwlock_timedrdlock +function will be automatically restarted after the thread returns from +the signal handler. +.Pp +The calling thread may deadlock if +at the time the call is made it holds a write lock on +.Fa rwlock . +The results are undefined if this function is called with +an uninitialized read-write lock. +.Sh IMPLEMENTATION NOTES +To prevent writer starvation, writers are favored over readers. +.Sh RETURN VALUES +If successful, the +.Fn pthread_rwlock_timedrdlock +function will return zero. +Otherwise, an error number will be returned to indicate the error. +.Pp +This function shall not return an error code of +.Er EINTR . +.Sh ERRORS +The +.Fn pthread_rwlock_timedrdlock +function will fail if: +.Bl -tag -width Er +.It Bq Er ETIMEDOUT +The lock could not be acquired before the specified timeout expired. +.El +.Pp +The +.Fn pthread_rwlock_timedrdlock +function may fail if: +.Bl -tag -width Er +.It Bq Er EAGAIN +The read lock could not be +acquired because the maximum number of read locks for +.Fa rwlock +would be exceeded. +.It Bq Er EDEADLK +The calling thread already holds a write lock on +.Fa rwlock . +.It Bq Er EINVAL +The value specified by +.Fa rwlock +does not refer to an initialized read-write lock object, +or the +.Fa abs_timeout +nanosecond value is less than zero or +greater than or equal to 1 billion. +.El +.Sh SEE ALSO +.Xr pthread_rwlock_init 3 , +.Xr pthread_rwlock_timedwrlock 3 , +.Xr pthread_rwlock_unlock 3 +.Sh STANDARDS +The +.Fn pthread_rwlock_timedrdlock +function is expected to conform to +.St -p1003.1-96 . +.Sh HISTORY +The +.Fn pthread_rwlock_timedrdlock +function first appeared in +.Fx 5.2 . |