PTHREAD_SPIN_DESTROY(3C) Standard C Library Functions

NAME

pthread_spin_destroy, pthread_spin_init - destroy or initialize a
spin lock object

SYNOPSIS

cc -mt [ flag... ] file... [ library... ]
#include <pthread.h>

int pthread_spin_destroy(pthread_spinlock_t *lock);


int pthread_spin_init(pthread_spinlock_t *lock, int pshared);

DESCRIPTION

The pthread_spin_destroy() function destroys 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 allocates 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 spin lock can 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 can 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 can be used for performing
synchronization.


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

RETURN VALUES

Upon successful completion, these functions returns 0. Otherwise, an
error number is returned to indicate the error.

ERRORS

The pthread_spin_init() function will fail if:

EAGAIN
The system lacks the necessary resources to initialize
another spin lock.


These functions may fail if:

EBUSY
The system 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.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+

SEE ALSO

pthread_spin_lock(3C), pthread_spin_unlock(3C), attributes(7),
standards(7)

January 30, 2004 PTHREAD_SPIN_DESTROY(3C)