man3p/pthread_rwlock_timedwrlock.3p

   1 .\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
   2 .TH "PTHREAD_RWLOCK_TIMEDWRLOCK" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
   3 .\" pthread_rwlock_timedwrlock
   4 .SH NAME
   5 pthread_rwlock_timedwrlock \- lock a read-write lock for writing
   6 .SH SYNOPSIS
   7 .LP
   8 \fB#include <pthread.h>
   9 .br
  10 #include <time.h>
  11 .br
  12 .sp
  13 int pthread_rwlock_timedwrlock(pthread_rwlock_t *restrict\fP \fIrwlock\fP\fB,
  14 .br
  15 \ \ \ \ \ \  const struct timespec *restrict\fP \fIabs_timeout\fP\fB);
  16 \fP
  17 \fB
  18 .br
  19 \fP
  20 .SH DESCRIPTION
  21 .LP
  22 The \fIpthread_rwlock_timedwrlock\fP() function shall apply a write
  23 lock to the read-write lock referenced by \fIrwlock\fP as
  24 in the \fIpthread_rwlock_wrlock\fP() function. However, if the lock
  25 cannot
  26 be acquired without waiting for other threads to unlock the lock,
  27 this wait shall be terminated when the specified timeout expires.
  28 The timeout shall expire when the absolute time specified by \fIabs_timeout\fP
  29 passes, as measured by the clock on which timeouts
  30 are based (that is, when the value of that clock equals or exceeds
  31 \fIabs_timeout\fP), or if the absolute time specified by
  32 \fIabs_timeout\fP has already been passed at the time of the call.
  33 .LP
  34 If the Timers option is supported, the timeout shall be based on the
  35 CLOCK_REALTIME clock.  If the Timers option is not supported, the
  36 timeout shall be based on the system clock as returned by the
  37 \fItime\fP() function. The resolution of the timeout shall be the
  38 resolution of the clock on
  39 which it is based. The \fBtimespec\fP data type is defined in the
  40 \fI<time.h>\fP
  41 header. Under no circumstances shall the function fail with a timeout
  42 if the lock can be acquired immediately. The validity of the
  43 \fIabs_timeout\fP parameter need not be checked if the lock can be
  44 immediately acquired.
  45 .LP
  46 If a signal that causes a signal handler to be executed is delivered
  47 to a thread blocked on a read-write lock via a call to
  48 \fIpthread_rwlock_timedwrlock\fP(), upon return from the signal handler
  49 the thread shall resume waiting for the lock as if it was
  50 not interrupted.
  51 .LP
  52 The calling thread may deadlock if at the time the call is made it
  53 holds the read-write lock. The results are undefined if this
  54 function is called with an uninitialized read-write lock.
  55 .SH RETURN VALUE
  56 .LP
  57 The \fIpthread_rwlock_timedwrlock\fP() function shall return zero
  58 if the lock for writing on the read-write lock object
  59 referenced by \fIrwlock\fP is acquired. Otherwise, an error number
  60 shall be returned to indicate the error.
  61 .SH ERRORS
  62 .LP
  63 The \fIpthread_rwlock_timedwrlock\fP() function shall fail if:
  64 .TP 7
  65 .B ETIMEDOUT
  66 The lock could not be acquired before the specified timeout expired.
  67 .sp
  68 .LP
  69 The \fIpthread_rwlock_timedwrlock\fP() function may fail if:
  70 .TP 7
  71 .B EDEADLK
  72 The calling thread already holds the \fIrwlock\fP.
  73 .TP 7
  74 .B EINVAL
  75 The value specified by rwlock does not refer to an initialized read-write
  76 lock object, or the \fIabs_timeout\fP nanosecond
  77 value is less than zero or greater than or equal to 1000 million.
  78 .sp
  79 .LP
  80 This function shall not return an error code of [EINTR].
  81 .LP
  82 \fIThe following sections are informative.\fP
  83 .SH EXAMPLES
  84 .LP
  85 None.
  86 .SH APPLICATION USAGE
  87 .LP
  88 Applications using this function may be subject to priority inversion,
  89 as discussed in the Base Definitions volume of
  90 IEEE\ Std\ 1003.1-2001, Section 3.285, Priority Inversion.
  91 .LP
  92 The \fIpthread_rwlock_timedwrlock\fP() function is part of the Threads
  93 and Timeouts options and need not be provided on all
  94 implementations.
  95 .SH RATIONALE
  96 .LP
  97 None.
  98 .SH FUTURE DIRECTIONS
  99 .LP
 100 None.
 101 .SH SEE ALSO
 102 .LP
 103 \fIpthread_rwlock_destroy\fP() , \fIpthread_rwlock_rdlock\fP() , \fIpthread_rwlock_timedrdlock\fP()
 104 , \fIpthread_rwlock_tryrdlock\fP() , \fIpthread_rwlock_trywrlock\fP()
 105 , \fIpthread_rwlock_unlock\fP() , \fIpthread_rwlock_wrlock\fP() ,
 106 the Base Definitions volume of IEEE\ Std\ 1003.1-2001, \fI<pthread.h>\fP,
 107 \fI<time.h>\fP
 108 .SH COPYRIGHT
 109 Portions of this text are reprinted and reproduced in electronic form
 110 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
 111 -- Portable Operating System Interface (POSIX), The Open Group Base
 112 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
 113 Electrical and Electronics Engineers, Inc and The Open Group. In the
 114 event of any discrepancy between this version and the original IEEE and
 115 The Open Group Standard, the original IEEE and The Open Group Standard
 116 is the referee document. The original Standard can be obtained online at
 117 http://www.opengroup.org/unix/online.html .