Performs an atomic compare and exchange operation. Prototypes _Bool atomic_compare_exchange_strong(volatile A *object, C *expected, C desired); Parameters A One of the atomic types. C The corresponding non-atomic type of A. object A pointer that points to the atomic object to test and modif...
3. atomic_exchange:交换一个原子对象中的值,并返回之前的值。 格式:`T atomic_exchange(_Atomic T* obj, T desired);` 4. atomic_compare_exchange_strong:使用强比较和交换操作,如果目标值与预期值相等,则替换为新值,并返回是否成功。 格式:`bool atomic_compare_exchange_strong(_Atomic T* obj, T* exp...
atomic_compare_exchange (属于 read-modify-write 操作) atomic_fetch_key (属于 read-modify-write 操作) 注: 上述同步操作相应的形参通常为, 指向原子类型的指针(而非直接使用原子类型). atomic_exchange 返回值: 返回值为比较结果. (1) bool atomic_compare_exchange_strong(volatile A *object, C *expecte...
std::vector<int> data; std::atomic<int> flag = {0}; void thread_1() { data.push_back(42); flag.store(1, std::memory_order_release); } void thread_2() { int expected=1; while (!flag.compare_exchange_strong(expected, 2, std::memory_order_acq_rel)) { expected = 1; } } ...
std::atomic<int>flag = {0}; void thread_1() { data.push_back(42); flag.store(1, std::memory_order_release); } void thread_2() { int expected=1; while (!flag.compare_exchange_strong(expected, 2, std::memory_order_acq_rel)) { ...
std::atomic<int> flag = {0}; voidthread_1() { data.push_back(42); flag.store(1, std::memory_order_release); } voidthread_2() { intexpected=1; while(!flag.compare_exchange_strong(expected,2, std::memory_order_acq_rel)) { ...
std::atomic<int> flag = {0};voidthread_1(){ data.push_back(42); flag.store(1, std::memory_order_release); }voidthread_2(){intexpected=1;while(!flag.compare_exchange_strong(expected,2, std::memory_order_acq_rel)) { expected =1; ...
随着科技的进步,现代多核处理器纷纷引入了无锁(Lock-Free)原子操作,比如比较与交换(Compare and Swap,简称CAS),加载时锁定/有条件存储(Load-locked Store-conditional,简称LL-SC)。x86处理器使用前者,Alpha、Power、MIPS、RISC-V、ARMv7、ARMv8等则使用后者,而从ARMv8.1开始也引入了CAS原子操作。LL-SC形式上虽然...
#include <thread>#include <atomic>#include <cassert>#include <vector> std::vector<int> data;std::atomic<int> flag = {0}; void thread_1(){ data.push_back(42); flag.store(1, std::memory_order_release);} void thread_2(){ int expected=1;while(!flag.compare_exchange_strong(expected...
flag.compare_exchange_strong(expected, 2, std::memory_order_acq_rel)) { expected = 1; } } void thread_3() { while (flag.load(std::memory_order_acquire) < 2) ; assert(data.at(0) == 42); // will never fire } int main() { std::thread a(thread_1); std::thread b(thread...