使用gcc内置CAS函数实现spinlock

最新推荐文章于 2023-01-04 15:31:40 发布

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最新推荐文章于 2023-01-04 15:31:40 发布 · 1.9k 阅读

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本文介绍了GCC中内置的原子比较并交换（CAS）函数__atomic_compare_exchange_n()，用于实现并发控制。通过示例展示了如何使用CAS函数创建spinlock，保证多线程环境下对共享资源的互斥访问。代码展示了如何在多线程程序中利用CAS进行同步，并最终达到无锁编程的效果。

gcc 里提供了内置 CAS 函数：__atomic_compare_exchange_n()，它的基本用法如下：

Built-in Function: bool __atomic_compare_exchange_n (type *ptr, type *expected, type desired, bool weak, int success_memorder, int failure_memorder)

This built-in function implements an atomic compare and exchange operation. This compares the contents of *ptr with the contents of *expected. If equal, the operation is a read-modify-write operation that writes desired into *ptr. If they are not equal, the operation is a read and the current contents of *ptr are written into *expected. weak is true for weak compare_exchange, which may fail spuriously, and false for the strong