man3p/pthread_spin_init.3p

   1 .\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
   2 .TH "PTHREAD_SPIN_DESTROY" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
   3 .\" pthread_spin_destroy
   4 .SH NAME
   5 pthread_spin_destroy, pthread_spin_init \- destroy or initialize a
   6 spin lock object (\fBADVANCED REALTIME
   7 THREADS\fP)
   8 .SH SYNOPSIS
   9 .LP
  10 \fB#include <pthread.h>
  11 .br
  12 .sp
  13 int pthread_spin_destroy(pthread_spinlock_t *\fP\fIlock\fP\fB);
  14 .br
  15 int pthread_spin_init(pthread_spinlock_t *\fP\fIlock\fP\fB, int\fP
  16 \fIpshared\fP\fB); \fP
  17 \fB
  18 .br
  19 \fP
  20 .SH DESCRIPTION
  21 .LP
  22 The \fIpthread_spin_destroy\fP() function shall destroy the spin lock
  23 referenced by \fIlock\fP and release any resources used
  24 by the lock. The effect of subsequent use of the lock is undefined
  25 until the lock is reinitialized by another call to
  26 \fIpthread_spin_init\fP(). The results are undefined if \fIpthread_spin_destroy\fP()
  27 is called when a thread holds the lock, or
  28 if this function is called with an uninitialized thread spin lock.
  29 .LP
  30 The \fIpthread_spin_init\fP() function shall allocate any resources
  31 required to use the spin lock referenced by \fIlock\fP and
  32 initialize the lock to an unlocked state.
  33 .LP
  34 If the Thread Process-Shared Synchronization option is supported and
  35 the value of \fIpshared\fP is PTHREAD_PROCESS_SHARED, the
  36 implementation shall permit the spin lock to be operated upon by any
  37 thread that has access to the memory where the spin lock is
  38 allocated, even if it is allocated in memory that is shared by multiple
  39 processes.
  40 .LP
  41 If the Thread Process-Shared Synchronization option is supported and
  42 the value of \fIpshared\fP is PTHREAD_PROCESS_PRIVATE,
  43 or if the option is not supported, the spin lock shall only be
  44 operated upon by threads created within the same process as the thread
  45 that initialized the spin lock. If threads of differing
  46 processes attempt to operate on such a spin lock, the behavior is
  47 undefined.
  48 .LP
  49 The results are undefined if \fIpthread_spin_init\fP() is called specifying
  50 an already initialized spin lock. The results are
  51 undefined if a spin lock is used without first being initialized.
  52 .LP
  53 If the \fIpthread_spin_init\fP() function fails, the lock is not initialized
  54 and the contents of \fIlock\fP are undefined.
  55 .LP
  56 Only the object referenced by \fIlock\fP may be used for performing
  57 synchronization.
  58 .LP
  59 The result of referring to copies of that object in calls to \fIpthread_spin_destroy\fP(),
  60 \fIpthread_spin_lock\fP(), \fIpthread_spin_trylock\fP(), or \fIpthread_spin_unlock\fP()
  61 is undefined.
  62 .SH RETURN VALUE
  63 .LP
  64 Upon successful completion, these functions shall return zero; otherwise,
  65 an error number shall be returned to indicate the
  66 error.
  67 .SH ERRORS
  68 .LP
  69 These functions may fail if:
  70 .TP 7
  71 .B EBUSY
  72 The implementation has detected an attempt to initialize or destroy
  73 a spin lock while it is in use (for example, while being
  74 used in a \fIpthread_spin_lock\fP() call) by another thread.
  75 .TP 7
  76 .B EINVAL
  77 The value specified by \fIlock\fP is invalid.
  78 .sp
  79 .LP
  80 The \fIpthread_spin_init\fP() function shall fail if:
  81 .TP 7
  82 .B EAGAIN
  83 The system lacks the necessary resources to initialize another spin
  84 lock.
  85 .TP 7
  86 .B ENOMEM
  87 Insufficient memory exists to initialize the lock.
  88 .sp
  89 .LP
  90 These functions shall not return an error code of [EINTR].
  91 .LP
  92 \fIThe following sections are informative.\fP
  93 .SH EXAMPLES
  94 .LP
  95 None.
  96 .SH APPLICATION USAGE
  97 .LP
  98 The \fIpthread_spin_destroy\fP() and \fIpthread_spin_init\fP() functions
  99 are part of the Spin Locks option and need not be
 100 provided on all implementations.
 101 .SH RATIONALE
 102 .LP
 103 None.
 104 .SH FUTURE DIRECTIONS
 105 .LP
 106 None.
 107 .SH SEE ALSO
 108 .LP
 109 \fIpthread_spin_lock\fP() , \fIpthread_spin_unlock\fP() , the Base
 110 Definitions volume of IEEE\ Std\ 1003.1-2001, \fI<pthread.h>\fP
 111 .SH COPYRIGHT
 112 Portions of this text are reprinted and reproduced in electronic form
 113 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
 114 -- Portable Operating System Interface (POSIX), The Open Group Base
 115 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
 116 Electrical and Electronics Engineers, Inc and The Open Group. In the
 117 event of any discrepancy between this version and the original IEEE and
 118 The Open Group Standard, the original IEEE and The Open Group Standard
 119 is the referee document. The original Standard can be obtained online at
 120 http://www.opengroup.org/unix/online.html .