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