NAME

pthread_spin_unlock — unlock a spin lock object

SYNOPSIS

#include <pthread.h>

int pthread_spin_unlock(pthread_spinlock_t *lock);


DESCRIPTION

The pthread_spin_unlock() function shall release the spin lock referenced by lock which was locked via the pthread_spin_lock() or pthread_spin_trylock() functions.

The results are undefined if the lock is not held by the calling thread.

If there are threads spinning on the lock when pthread_spin_unlock() is called, the lock becomes available and an unspecified spinning thread shall acquire the lock.

The results are undefined if this function is called with an uninitialized thread spin lock.

RETURN VALUE

Upon successful completion, the pthread_spin_unlock() function shall return zero; otherwise, an error number shall be returned to indicate the error.

ERRORS

This function shall not return an error code of [EINTR].

EXAMPLES

None.

APPLICATION USAGE

None.

RATIONALE

If an implementation detects that the value specified by the lock argument to pthread_spin_unlock() does not refer to an initialized spin lock object, it is recommended that the function should fail and report an [EINVAL] error.

If an implementation detects that the value specified by the lock argument to pthread_spin_unlock() refers to a spin lock object for which the current thread does not hold the lock, it is recommended that the function should fail and report an [EPERM] error.

FUTURE DIRECTIONS

None.

SEE ALSO

pthread_spin_destroy, pthread_spin_lock

XBD 4.15.2 Memory Synchronization, <pthread.h>

CHANGE HISTORY

First released in Issue 6. Derived from IEEE Std 1003.1j-2000.

In the SYNOPSIS, the inclusion of <sys/types.h> is no longer required.

Issue 7

The pthread_spin_unlock() function is moved from the Spin Locks option to the Base.

The [EINVAL] error for an uninitialized spin lock object is removed; this condition results in undefined behavior.

The [EPERM] error for a spin lock object for which the current thread does not hold the lock is removed; this condition results in undefined behavior.