1PTHREAD_RWLOCK_TIMEDWRLOCK(PP)OSIX Programmer's ManuPaTlHREAD_RWLOCK_TIMEDWRLOCK(P)
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NAME

6       pthread_rwlock_timedwrlock - lock a read-write lock for writing
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SYNOPSIS

9       #include <pthread.h>
10       #include <time.h>
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12       int pthread_rwlock_timedwrlock(pthread_rwlock_t *restrict rwlock,
13              const struct timespec *restrict abs_timeout);
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DESCRIPTION

17       The  pthread_rwlock_timedwrlock()  function shall apply a write lock to
18       the   read-write   lock   referenced    by    rwlock    as    in    the
19       pthread_rwlock_wrlock()  function.  However,  if  the  lock  cannot  be
20       acquired without waiting for other threads to  unlock  the  lock,  this
21       wait shall be terminated when the specified timeout expires.  The time‐
22       out shall expire  when  the  absolute  time  specified  by  abs_timeout
23       passes,  as measured by the clock on which timeouts are based (that is,
24       when the value of that clock equals or exceeds abs_timeout), or if  the
25       absolute  time  specified by abs_timeout has already been passed at the
26       time of the call.
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28       If the Timers option is supported, the timeout shall be  based  on  the
29       CLOCK_REALTIME clock.  If the Timers option is not supported, the time‐
30       out shall be based on the system clock as returned by the time()  func‐
31       tion.  The  resolution  of  the  timeout shall be the resolution of the
32       clock on which it is based. The timespec data type is  defined  in  the
33       <time.h>  header. Under no circumstances shall the function fail with a
34       timeout if the lock can be acquired immediately. The  validity  of  the
35       abs_timeout  parameter  need  not be checked if the lock can be immedi‐
36       ately acquired.
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38       If a signal that causes a signal handler to be executed is delivered to
39       a   thread   blocked   on   a   read-write   lock   via   a   call   to
40       pthread_rwlock_timedwrlock(), upon return from the signal  handler  the
41       thread shall resume waiting for the lock as if it was not interrupted.
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43       The  calling  thread  may  deadlock  if at the time the call is made it
44       holds the read-write lock. The results are undefined if  this  function
45       is called with an uninitialized read-write lock.
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RETURN VALUE

48       The pthread_rwlock_timedwrlock() function shall return zero if the lock
49       for writing on the read-write  lock  object  referenced  by  rwlock  is
50       acquired.  Otherwise, an error number shall be returned to indicate the
51       error.
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ERRORS

54       The pthread_rwlock_timedwrlock() function shall fail if:
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56       ETIMEDOUT
57              The lock could not be  acquired  before  the  specified  timeout
58              expired.
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61       The pthread_rwlock_timedwrlock() function may fail if:
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63       EDEADLK
64              The calling thread already holds the rwlock.
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66       EINVAL The  value  specified by rwlock does not refer to an initialized
67              read-write lock object, or the abs_timeout nanosecond  value  is
68              less than zero or greater than or equal to 1000 million.
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71       This function shall not return an error code of [EINTR].
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73       The following sections are informative.
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EXAMPLES

76       None.
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APPLICATION USAGE

79       Applications  using this function may be subject to priority inversion,
80       as discussed in the Base Definitions  volume  of  IEEE Std 1003.1-2001,
81       Section 3.285, Priority Inversion.
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83       The  pthread_rwlock_timedwrlock()  function  is part of the Threads and
84       Timeouts options and need not be provided on all implementations.
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RATIONALE

87       None.
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FUTURE DIRECTIONS

90       None.
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SEE ALSO

93       pthread_rwlock_destroy()       ,       pthread_rwlock_rdlock()        ,
94       pthread_rwlock_timedrdlock()     ,     pthread_rwlock_tryrdlock()     ,
95       pthread_rwlock_trywrlock()      ,       pthread_rwlock_unlock()       ,
96       pthread_rwlock_wrlock()    ,    the    Base   Definitions   volume   of
97       IEEE Std 1003.1-2001, <pthread.h>, <time.h>
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100       Portions of this text are reprinted and reproduced in  electronic  form
101       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
102       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
103       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
104       Electrical and Electronics Engineers, Inc and The Open  Group.  In  the
105       event of any discrepancy between this version and the original IEEE and
106       The Open Group Standard, the original IEEE and The Open Group  Standard
107       is  the  referee document. The original Standard can be obtained online
108       at http://www.opengroup.org/unix/online.html .
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112IEEE/The Open Group                  2003        PTHREAD_RWLOCK_TIMEDWRLOCK(P)
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