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pthread_spin_trylock(3c) [opensolaris man page]

pthread_spin_lock(3C)					   Standard C Library Functions 				     pthread_spin_lock(3C)

NAME
pthread_spin_lock, pthread_spin_trylock - lock a spin lock object SYNOPSIS
cc -mt [ flag... ] file... [ library... ] #include <pthread.h> int pthread_spin_lock(pthread_spinlock_t *lock); #include <pthread.h> int pthread_spin_trylock(pthread_spinlock_t *lock); DESCRIPTION
The pthread_spin_lock() function locks the spin lock referenced by lock. The calling thread acquires the lock if it is not held by another thread. Otherwise, the thread spins (that is, does 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 locks the spin lock referenced by lock if it is not held by any thread. Otherwise, the function fails. The results are undefined if either of these functions is called with an uninitialized spin lock. RETURN VALUES
Upon successful completion, these functions returns 0. Otherwise, an error number is returned to indicate the error. ERRORS
The pthread_spin_trylock() function will fail if: EBUSY A thread currently holds the lock. These functions may fail if: EINVAL The value specified by lock does not refer to an initialized spin lock object. The pthread_spin_lock() function may fail if: EDEADLK The calling thread already holds the lock. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ SEE ALSO
pthread_spin_destroy(3C), pthread_spin_unlock(3C), attributes(5), standards(5) SunOS 5.11 30 Jan 2004 pthread_spin_lock(3C)

Check Out this Related Man Page

PTHREAD_SPIN(3) 					   BSD Library Functions Manual 					   PTHREAD_SPIN(3)

NAME
pthread_spin -- spin lock interface LIBRARY
POSIX Threads Library (libpthread, -lpthread) SYNOPSIS
#include <pthread.h> int pthread_spin_init(pthread_spinlock_t *lock, int pshared); int pthread_spin_destroy(pthread_spinlock_t *lock); int pthread_spin_lock(pthread_spinlock_t *lock); int pthread_spin_trylock(pthread_spinlock_t *lock); int pthread_spin_unlock(pthread_spinlock_t *lock); DESCRIPTION
The pthread_spin_init() function is used to initialize a spin lock. In the NetBSD implementation the pshared parameter is currently unused and all spin locks exhibit the PTHREAD_PROCESS_SHARED property, implying that all spin locks may be accessed by threads of multiple pro- cesses. The results of calling pthread_spin_init() with an already initialized lock are undefined. The pthread_spin_destroy() function is used to destroy a spin lock previously created with pthread_spin_init(). It is undefined what happens if the function is called when a thread holds the lock, or if the function is called with an uninitialized spin lock. The pthread_spin_lock() function acquires a spin lock on lock, provided that lock is not presently held. If the lock cannot be immediately acquired, the calling thread repeatedly retries until it can acquire the lock. Undefined behavior may follow if the calling thread holds the lock at the time the call is made. The pthread_spin_trylock() function performs the same locking action, but does not block if the lock cannot be immediately obtained; if the lock is held, the call fails. The pthread_spin_unlock() function is used to release the read/write lock previously obtained by pthread_spin_lock() or pthread_spin_trylock(). The results are undefined if the lock is not held by the calling thread. RETURN VALUES
If successful, all described functions return zero. Otherwise an error number will be returned to indicate the error. ERRORS
The pthread_spin_init() function shall fail if: [ENOMEM] Insufficient memory exists to initialize the lock. The pthread_spin_init() function may fail if: [EINVAL] The lock parameter was NULL or the pshared parameter was neither PTHREAD_PROCESS_SHARED nor PTHREAD_PROCESS_PRIVATE. The pthread_spin_destroy() function may fail if: [EBUSY] The system has detected an attempt to destroy the object referenced by lock while it is locked. [EINVAL] The value specified by lock is invalid. The pthread_spin_trylock() function shall fail if: [EBUSY] The lock could not be acquired because a writer holds the lock or was blocked on it. The pthread_spin_lock() function may fail if: [EDEADLK] The current thread already owns lock for writing. The pthread_spin_lock() and pthread_spin_trylock() functions may fail if: [EINVAL] The value specified by lock is invalid. The pthread_spin_unlock() function may fail if: [EINVAL] The value specified by lock is invalid. SEE ALSO
pthread(3), pthread_barrier(3), pthread_cond(3), pthread_mutex(3), pthread_rwlock(3) STANDARDS
These functions conform to IEEE Std 1003.1-2001 (``POSIX.1''). CAVEATS
Applications using spin locks are vulnerable to the effects of priority inversion. Applications using real-time threads (SCHED_FIFO), (SCHED_RR) should not use these interfaces. Outside carefully controlled environments, priority inversion with spin locks can lead to system deadlock. Mutexes are preferable in nearly every possible use case. BSD
July 8, 2010 BSD
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