NAME
pthread_spin_lock
pthread_spin_trylock — lock
a spin lock object
SYNOPSIS
#include
<pthread.h>
int pthread_spin_lock(pthread_spinlock_t *lock); int pthread_spin_trylock(pthread_spinlock_t *lock);
DESCRIPTION
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.
RETURN VALUE
Upon successful completion, these functions shall return zero; otherwise, an error number shall be returned to indicate the error.
ERRORS
The pthread_spin_lock () function may fail
if:
- [EDEADLK]
- A deadlock condition was detected.
The pthread_spin_trylock () function shall
fail if:
- [EBUSY]
- A thread currently holds the lock.
These functions shall not return an error code of [EINTR].
EXAMPLES
None.
APPLICATION USAGE
Applications using this function may be subject to priority inversion, as discussed in XBD V1_chap03(7) .
RATIONALE
If an implementation detects that the value specified by the
lock argument to pthread_spin_lock
() or pthread_spin_trylock () 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_lock
() refers to a spin lock object for which the calling thread already holds
the lock, it is recommended that the function should fail and report an
[EDEADLK] error.
FUTURE DIRECTIONS
None.
SEE ALSO
pthread_spin_destroy(3) , pthread_spin_unlock(3)
XBD V1_chap03(7) , V1_chap04(7) , <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.
IEEE Std 1003.1-2001 (“POSIX.1”)/Cor 2-2004, item XSH/TC2/D6/107 is applied, updating the ERRORS section so that the [EDEADLK] error includes detection of a deadlock condition.
Issue 7
The pthread_spin_lock () and
pthread_spin_trylock () functions are 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 [EDEADLK] error for a spin lock object for which the calling thread already holds the lock is removed; this condition results in undefined behavior.