"PTHREAD_SPIN_DESTROY"(P) manual page

From 41f88a82b33cdb357c83b582381232733ed2d039 Mon Sep 17 00:00:00 2001 From: rpj Date: Thu, 5 May 2005 14:18:27 +0000 Subject: '' --- manual/pthread_spin_init.html | 174 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 174 insertions(+) create mode 100644 manual/pthread_spin_init.html (limited to 'manual/pthread_spin_init.html') diff --git a/manual/pthread_spin_init.html b/manual/pthread_spin_init.html new file mode 100644 index 0000000..cd608f6 --- /dev/null +++ b/manual/pthread_spin_init.html @@ -0,0 +1,174 @@ + + + + + "PTHREAD_SPIN_DESTROY"(P) manual page + + + + + + + +

Table of Contents

Name

pthread_spin_destroy, pthread_spin_init - destroy or initialize a +spin lock object (ADVANCED REALTIME THREADS) +

Synopsis

#include <pthread.h> +

pthread_spinlock_t lock = +PTHREAD_SPINLOCK_INITIALIZER;

int pthread_spin_destroy(pthread_spinlock_t *lock); +
int pthread_spin_init(pthread_spinlock_t *lock, int +pshared); +

Description

The pthread_spin_destroy function shall destroy the spin +lock referenced by lock 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 pthread_spin_init . +The results are undefined if pthread_spin_destroy is called +when a thread holds the lock, or if this function is called with an +uninitialized thread spin lock. +

The pthread_spin_init function shall allocate any resources +required to use the spin lock referenced by lock and +initialize the lock to an unlocked state. +

Pthreads-w32 supports single and multiple processor systems +as well as process CPU affinity masking by checking the mask when the +spin lock is initialized. If the process is using only a single +processor at the time pthread_spin_init is called then the +spin lock is initialized as a PTHREAD_MUTEX_NORMAL mutex object. A +thread that calls pthread_spin_lock(3) +will block rather than spin in this case. If the process CPU affinity +mask is altered after the spin lock has been initialised, the spin +lock is not modified, and may no longer be optimal for the number of +CPUs available.

Pthreads-w32 defines _POSIX_THREAD_PROCESS_SHARED in +pthread.h as -1 to indicate that these routines do not support the +PTHREAD_PROCESS_SHARED attribute. pthread_spin_init +will return the error ENOTSUP if the value of pshared +is not PTHREAD_PROCESS_PRIVATE.

The results are undefined if pthread_spin_init is called +specifying an already initialized spin lock. The results are +undefined if a spin lock is used without first being initialized. +

If the pthread_spin_init function fails, the lock is not +initialized and the contents of lock are undefined. +

Only the object referenced by lock may be used for +performing synchronization. +

The result of referring to copies of that object in calls to +pthread_spin_destroy , pthread_spin_lock(3) +, pthread_spin_trylock(3), +or pthread_spin_unlock(3) +is undefined. +

Pthreads-w32 supports statically initialized spin locks +using PTHREAD_SPINLOCK_INITIALIZER. An application should +still call pthread_spin_destroy at some point to ensure that +any resources consumed by the spin lock are released.

Return Value

Upon successful completion, these functions shall return zero; +otherwise, an error number shall be returned to indicate the error. +

Errors

These functions may fail if: +

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 + pthread_spin_lock(3) + call) by another thread. +
+ EINVAL +: + The value specified by lock is invalid. +

+The pthread_spin_init function shall fail if: +

ENOTSUP +: + The value of pshared is not PTHREAD_PROCESS_PRIVATE.
+ ENOMEM +: + Insufficient memory exists to initialize the lock. +

+These functions shall not return an error code of [EINTR]. +

The following sections are informative. +

Examples

None. +

Application Usage

The pthread_spin_destroy and pthread_spin_init +functions are part of the Spin Locks option and need not be provided +on all implementations. +

Rationale

None. +

Future Directions

None. +

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 +. +

Modified by Ross Johnson for use with Pthreads-w32.

Table of Contents

Name +
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Synopsis +
+
Description +
+
Return + Value +
+
Errors +
+
Examples +
+
Application + Usage +
+
Rationale +
+
Future + Directions +
+
See + Also +
+
Copyright +
+

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