PROLOG

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

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(3POSIX)