objective-c - BOOL 在 Objective C 中是读/写原子的吗？

Question

当两个线程“同时”将 BOOL 设置为 YES 时会发生什么？

Answer 1

这是 Jacko 建议的解决方案的代码.
将 volatile uint32_t 与 OSAtomicOr32Barrier 和 OSAtomicAnd32Barrier

一起使用

#import <libkern/OSAtomic.h>

volatile uint32_t _IsRunning;

- (BOOL)isRunning {
    return _IsRunning != 0;
}

- (void)setIsRunning:(BOOL)allowed {

    if (allowed) {
        OSAtomicOr32Barrier(1, & _IsRunning); //Atomic bitwise OR of two 32-bit values with barrier
    } else {
        OSAtomicAnd32Barrier(0, & _IsRunning); //Atomic bitwise AND of two 32-bit values with barrier.
    }
}