pthread_spin_unlock(3)

1pthread_spin_lock(3)       Library Functions Manual       pthread_spin_lock(3)
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NAME

6       pthread_spin_lock, pthread_spin_trylock, pthread_spin_unlock - lock and
7       unlock a spin lock
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LIBRARY

10       POSIX threads library (libpthread, -lpthread)
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SYNOPSIS

13       #include <pthread.h>
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15       int pthread_spin_lock(pthread_spinlock_t *lock);
16       int pthread_spin_trylock(pthread_spinlock_t *lock);
17       int pthread_spin_unlock(pthread_spinlock_t *lock);
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19   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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21       pthread_spin_lock(), pthread_spin_trylock():
22           _POSIX_C_SOURCE >= 200112L
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DESCRIPTION

25       The pthread_spin_lock() function locks the spin  lock  referred  to  by
26       lock.   If  the spin lock is currently unlocked, the calling thread ac‐
27       quires the lock immediately.  If the spin lock is currently  locked  by
28       another thread, the calling thread spins, testing the lock until it be‐
29       comes available, at which point the calling thread acquires the lock.
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31       Calling pthread_spin_lock() on a lock  that  is  already  held  by  the
32       caller    or    a   lock   that   has   not   been   initialized   with
33       pthread_spin_init(3) results in undefined behavior.
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35       The pthread_spin_trylock() function is like pthread_spin_lock(), except
36       that  if  the  spin lock referred to by lock is currently locked, then,
37       instead of spinning, the call returns immediately with the error EBUSY.
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39       The pthread_spin_unlock() function unlocks the spin  lock  referred  to
40       lock.   If  any  threads are spinning on the lock, one of those threads
41       will then acquire the lock.
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43       Calling pthread_spin_unlock() on a lock that is not held by the  caller
44       results in undefined behavior.
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RETURN VALUE

47       On  success,  these  functions return zero.  On failure, they return an
48       error number.
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ERRORS

51       pthread_spin_lock() may fail with the following errors:
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53       EDEADLOCK
54              The system detected a deadlock condition.
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56       pthread_spin_trylock() fails with the following errors:
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58       EBUSY  The spin lock is currently locked by another thread.
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STANDARDS

61       POSIX.1-2008.
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HISTORY

64       glibc 2.2.  POSIX.1-2001.
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CAVEATS

67       Applying any of the functions described on this page to  an  uninitial‐
68       ized spin lock results in undefined behavior.
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70       Carefully read NOTES in pthread_spin_init(3).
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