线程安全、无锁的增量函数？

Question

更新：在 C 或 C++ 中可用的所有 Linux 发行版上是否有线程安全、无锁和可用的增量函数？

Answer 1

GLib has functions to do this. You might check out http://library.gnome.org/devel/glib/stable/glib-Atomic-Operations.html

Specifically, it sounds like you want g_atomic_int_inc()

Answer 2

I think these are GNU extensions, and processor specific, but have a look at GNU C Atomic Builtins .

I think there are also atomic "libraries" available that use inline assembly etc. to provide such features.

Answer 3

The current C and C++ standards don't define such a thing. Your implementation may well have one.

Answer 4

2021 answer

12 years have passed since the other answers and it is now in the standard and it is possible to do this since C++11 using the atomic operations library .

#include <iostream>
#include <atomic>

int main() {
    std::atomic<int> atomic_i{5};
    std::cout << atomic_i.is_lock_free() << std::endl; // 1, which means lock free
    atomic_i++;
    std::cout << atomic_i << std::endl; // 6
    return 0;
}

If you want a normal, non-atomic integer that you want to increment in atomic operations only sometimes, you can do this:

int j = 8;
j = ++std::atomic<int>(j);
std::cout << j  << std::endl; // 9