PTHREAD_RWLOCK_TIMEDWRLOCK(3P)OSIX Programmer's ManuPaTlHREAD_RWLOCK_TIMEDWRLOCK(3)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

NAME
       pthread_rwlock_timedwrlock -- lock a read-write lock for writing

SYNOPSIS
       #include <pthread.h>
       #include <time.h>

       int pthread_rwlock_timedwrlock(pthread_rwlock_t *restrict rwlock,
           const struct timespec *restrict abstime);

DESCRIPTION
       The pthread__rwlock__timedwrlock() function shall apply a write lock to
       the read-write lock referenced by rwlock as in the
       pthread__rwlock__wrlock() function. However, if the lock cannot be
       acquired without waiting for other threads to unlock the lock, this
       wait shall be terminated when the specified timeout expires. The
       timeout shall expire when the absolute time specified by abstime
       passes, as measured by the clock on which timeouts are based (that is,
       when the value of that clock equals or exceeds abstime), or if the
       absolute time specified by abstime has already been passed at the time
       of the call.

       The timeout shall be based on the CLOCK_REALTIME clock.  The resolution
       of the timeout shall be the resolution of the CLOCK_REALTIME clock. The
       timespec data type is defined in the <time.h> header. Under no
       circumstances shall the function fail with a timeout if the lock can be
       acquired immediately. The validity of the abstime 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 via a call to
       pthread__rwlock__timedwrlock(), upon return from the signal handler the
       thread shall resume waiting for the lock as if it was not interrupted.

       The calling thread may deadlock if at the time the call is made it
       holds the read-write lock. The results are undefined if this function
       is called with an uninitialized read-write lock.

RETURN VALUE
       The pthread__rwlock__timedwrlock() function shall return zero if the lock
       for writing on the read-write lock object referenced by rwlock is
       acquired. Otherwise, an error number shall be returned to indicate the
       error.

ERRORS
       The pthread__rwlock__timedwrlock() function shall fail if:

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

       The pthread__rwlock__timedwrlock() function may fail if:

       EDEADLK
              A deadlock condition was detected or the calling thread already
              holds the rwlock.

       EINVAL The abstime nanosecond value is less than zero or greater than
              or equal to 1000 million.

       This function shall not return an error code of [EINTR].

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       Applications using this function may be subject to priority inversion,
       as discussed in the Base Definitions volume of POSIX.1-2017, Section
       3.291, Priority Inversion.

RATIONALE
       If an implementation detects that the value specified by the rwlock
       argument to pthread__rwlock__timedwrlock() does not refer to an
       initialized read-write lock object, it is recommended that the function
       should fail and report an [EINVAL] error.

FUTURE DIRECTIONS
       None.

SEE ALSO
       pthread__rwlock__destroy(), pthread__rwlock__rdlock(),
       pthread__rwlock__timedrdlock(), pthread__rwlock__trywrlock(),
       pthread__rwlock__unlock()

       The Base Definitions volume of POSIX.1-2017, Section 3.291, Priority
       Inversion, Section 4.12, Memory Synchronization, <pthread.h>, <time.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  In the event of any discrepancy between this version and the
       original IEEE and The Open Group Standard, the original IEEE and The
       Open Group Standard is the referee document. The original Standard can
       be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017        PTHREAD_RWLOCK_TIMEDWRLOCK(3)
