Originální popis anglicky:
pthread_spin_destroy, pthread_spin_init - destroy or initialize a spin lock
object (
ADVANCED REALTIME THREADS)
Návod, kniha: POSIX Programmer's Manual
#include <pthread.h>
int pthread_spin_destroy(pthread_spinlock_t *
lock);
int pthread_spin_init(pthread_spinlock_t *
lock,
int pshared);
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.
If the Thread Process-Shared Synchronization option is supported and the value
of
pshared 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.
If the Thread Process-Shared Synchronization option is supported and the value
of
pshared 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.
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(),
pthread_spin_trylock(), or
pthread_spin_unlock() is undefined.
Upon successful completion, these functions shall return zero; otherwise, an
error number shall be returned to indicate the error.
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() call) by another thread.
- EINVAL
- The value specified by lock is invalid.
The
pthread_spin_init() function shall fail if:
- EAGAIN
- The system lacks the necessary resources to initialize
another spin lock.
- ENOMEM
- Insufficient memory exists to initialize the lock.
These functions shall not return an error code of [EINTR].
The following sections are informative.
None.
The
pthread_spin_destroy() and
pthread_spin_init() functions are
part of the Spin Locks option and need not be provided on all implementations.
None.
None.
pthread_spin_lock() ,
pthread_spin_unlock() , the Base Definitions
volume of IEEE Std 1003.1-2001,
<pthread.h>
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
.
