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.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
.TH "PTHREAD_SPIN_DESTROY" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\" pthread_spin_destroy
.SH NAME
pthread_spin_destroy, pthread_spin_init \- destroy or initialize a
spin lock object (\fBADVANCED REALTIME
THREADS\fP)
.SH SYNOPSIS
.LP
\fB#include <pthread.h>
.br
.sp
int pthread_spin_destroy(pthread_spinlock_t *\fP\fIlock\fP\fB);
.br
int pthread_spin_init(pthread_spinlock_t *\fP\fIlock\fP\fB, int\fP
\fIpshared\fP\fB); \fP
\fB
.br
\fP
.SH DESCRIPTION
.LP
The \fIpthread_spin_destroy\fP() function shall destroy the spin lock
referenced by \fIlock\fP and release any resources used
by the lock. The effect of subsequent use of the lock is undefined
until the lock is reinitialized by another call to
\fIpthread_spin_init\fP(). The results are undefined if \fIpthread_spin_destroy\fP()
is called when a thread holds the lock, or
if this function is called with an uninitialized thread spin lock.
.LP
The \fIpthread_spin_init\fP() function shall allocate any resources
required to use the spin lock referenced by \fIlock\fP and
initialize the lock to an unlocked state.
.LP
If the Thread Process-Shared Synchronization option is supported and
the value of \fIpshared\fP is PTHREAD_PROCESS_SHARED, the
implementation shall permit the spin lock to be operated upon by any
thread that has access to the memory where the spin lock is
allocated, even if it is allocated in memory that is shared by multiple
processes.
.LP
If the Thread Process-Shared Synchronization option is supported and
the value of \fIpshared\fP is PTHREAD_PROCESS_PRIVATE,
or if the option is not supported, the spin lock shall only be
operated upon by threads created within the same process as the thread
that initialized the spin lock. If threads of differing
processes attempt to operate on such a spin lock, the behavior is
undefined.
.LP
The results are undefined if \fIpthread_spin_init\fP() is called specifying
an already initialized spin lock. The results are
undefined if a spin lock is used without first being initialized.
.LP
If the \fIpthread_spin_init\fP() function fails, the lock is not initialized
and the contents of \fIlock\fP are undefined.
.LP
Only the object referenced by \fIlock\fP may be used for performing
synchronization.
.LP
The result of referring to copies of that object in calls to \fIpthread_spin_destroy\fP(),
\fIpthread_spin_lock\fP(), \fIpthread_spin_trylock\fP(), or \fIpthread_spin_unlock\fP()
is undefined.
.SH RETURN VALUE
.LP
Upon successful completion, these functions shall return zero; otherwise,
an error number shall be returned to indicate the
error.
.SH ERRORS
.LP
These functions may fail if:
.TP 7
.B EBUSY
The implementation has detected an attempt to initialize or destroy
a spin lock while it is in use (for example, while being
used in a \fIpthread_spin_lock\fP() call) by another thread.
.TP 7
.B EINVAL
The value specified by \fIlock\fP is invalid.
.sp
.LP
The \fIpthread_spin_init\fP() function shall fail if:
.TP 7
.B EAGAIN
The system lacks the necessary resources to initialize another spin
lock.
.TP 7
.B ENOMEM
Insufficient memory exists to initialize the lock.
.sp
.LP
These functions shall not return an error code of [EINTR].
.LP
\fIThe following sections are informative.\fP
.SH EXAMPLES
.LP
None.
.SH APPLICATION USAGE
.LP
The \fIpthread_spin_destroy\fP() and \fIpthread_spin_init\fP() functions
are part of the Spin Locks option and need not be
provided on all implementations.
.SH RATIONALE
.LP
None.
.SH FUTURE DIRECTIONS
.LP
None.
.SH SEE ALSO
.LP
\fIpthread_spin_lock\fP() , \fIpthread_spin_unlock\fP() , the Base
Definitions volume of IEEE\ Std\ 1003.1-2001, \fI<pthread.h>\fP
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 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 .
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