__thread 可以用作局部变量吗

Question

我有这样一个使用静态变量的函数。现在我需要在多线程应用程序中使用它。

char *
ether_ntoa(const struct ether_addr *n)
{
    static char a[18];
    return (ether_ntoa_r(n, a));
}

我可以改用 __thread 变量吗？

char *
ether_ntoa(const struct ether_addr *n)
{
   __thread char a[18];
   return (ether_ntoa_r(n, a));
}

我知道我可以向 ether_ntoa 函数添​​加另一个参数，但想知道这是否也能正常工作？

Answer 1

是的，这会起作用，但保留 static 说明符。来自gcc docs :

The __thread specifier may be used alone, with the extern or static specifiers, but with no other storage class specifier. When used with extern or static, __thread must appear immediately after the other storage class specifier.

The __thread specifier may be applied to any global, file-scoped static, function-scoped static, or static data member of a class. It may not be applied to block-scoped automatic or non-static data member.