int pthread_spin_lock(pthread_spinlock_t *lock);
int pthread_spin_trylock(pthread_spinlock_t *lock);
The pthread_spin_lock() function shall lock the spin lock referenced by lock. The calling thread shall acquire the lock if it is not held by another thread. Otherwise, the thread shall spin (that is, shall not return from the pthread_spin_lock() call) until the lock becomes available. The results are undefined if the calling thread holds the lock at the time the call is made. The pthread_spin_trylock() function shall lock the spin lock referenced by lock if it is not held by any thread. Otherwise, the function shall fail.
The results are undefined if any of these functions is called with an uninitialized spin lock.
Upon successful completion, these functions shall return zero; otherwise, an error number shall be returned to indicate the error.
These functions may fail if:
The value specified by lock does not refer to an initialized
spin lock object.
The pthread_spin_lock() function may fail if:
The calling thread already holds the lock.
The pthread_spin_trylock() function shall fail if:
A thread currently holds the lock.
These functions shall not return an error code of [EINTR].
The following sections are informative.
Applications using this function may be subject to priority inversion, as discussed in the Base Definitions volume of IEEE Std 1003.1-2001, Section 3.285, Priority Inversion.
The pthread_spin_lock() and pthread_spin_trylock() functions are part of the Spin Locks option and need not be provided on all implementations.
COPYRIGHTPortions 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 .