1 //===-- Implementation of pthread_spin_destroy function -------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "src/pthread/pthread_spin_destroy.h" 10 #include "hdr/errno_macros.h" 11 #include "src/__support/common.h" 12 #include "src/__support/threads/spin_lock.h" 13 namespace LIBC_NAMESPACE_DECL { 14 15 static_assert(sizeof(pthread_spinlock_t::__lockword) == sizeof(SpinLock) && 16 alignof(decltype(pthread_spinlock_t::__lockword)) == 17 alignof(SpinLock), 18 "pthread_spinlock_t::__lockword and SpinLock must be of the same " 19 "size and alignment"); 20 21 LLVM_LIBC_FUNCTION(int, pthread_spin_destroy, 22 ([[maybe_unused]] pthread_spinlock_t * lock)) { 23 // If an implementation detects that the value specified by the lock argument 24 // to pthread_spin_lock() or pthread_spin_trylock() does not refer to an 25 // initialized spin lock object, it is recommended that the function should 26 // fail and report an [EINVAL] error. 27 if (!lock) 28 return EINVAL; 29 auto spin_lock = reinterpret_cast<SpinLock *>(&lock->__lockword); 30 if (!spin_lock || spin_lock->is_invalid()) 31 return EINVAL; 32 33 // If an implementation detects that the value specified by the lock argument 34 // to pthread_spin_destroy() or pthread_spin_init() refers to a locked spin 35 // lock object, or detects that the value specified by the lock argument to 36 // pthread_spin_init() refers to an already initialized spin lock object, it 37 // is recommended that the function should fail and report an [EBUSY] error. 38 if (spin_lock->is_locked()) 39 return EBUSY; 40 41 // poison the lock 42 spin_lock->~SpinLock(); 43 lock->__owner = 0; 44 return 0; 45 } 46 47 } // namespace LIBC_NAMESPACE_DECL 48