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"
13namespace LIBC_NAMESPACE_DECL {
14
15static_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
21LLVM_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

source code of libc/src/pthread/pthread_spin_destroy.cpp