1 //===-- Implementation of pthread_spin_init 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_init.h" 10 #include "hdr/errno_macros.h" 11 #include "src/__support/CPP/new.h" 12 #include "src/__support/common.h" 13 #include "src/__support/threads/spin_lock.h" 14 #include <pthread.h> // for PTHREAD_PROCESS_SHARED, PTHREAD_PROCESS_PRIVATE 15 16 namespace LIBC_NAMESPACE_DECL { 17 18 static_assert(sizeof(pthread_spinlock_t::__lockword) == sizeof(SpinLock) && 19 alignof(decltype(pthread_spinlock_t::__lockword)) == 20 alignof(SpinLock), 21 "pthread_spinlock_t::__lockword and SpinLock must be of the same " 22 "size and alignment"); 23 24 LLVM_LIBC_FUNCTION(int, pthread_spin_init, 25 (pthread_spinlock_t * lock, [[maybe_unused]] int pshared)) { 26 if (!lock) 27 return EINVAL; 28 if (pshared != PTHREAD_PROCESS_SHARED && pshared != PTHREAD_PROCESS_PRIVATE) 29 return EINVAL; 30 // The spin lock here is a simple atomic flag, so we don't need to do any 31 // special handling for pshared. 32 ::new (&lock->__lockword) SpinLock(); 33 lock->__owner = 0; 34 return 0; 35 } 36 37 } // namespace LIBC_NAMESPACE_DECL 38