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/*

# atomic

More restricted than mutex as it can only protect a few operations on integers.

But if that is the use case, may be more efficient.

On GCC 4.8 x86-64, using atomic is a huge peformance improvement

over the same program with mutexes (5x).

*/

#include "common.hpp"

#if __cplusplus >= 201103L

std::atomic_long global(0);

void threadMain() {

for (int i = 0; i < NUM_ITERS; ++i) {

global++;

}

}

#endif

int main() {

#if __cplusplus >= 201103L

std::thread threads[NUM_THREADS];

int i;

for (i = 0; i < NUM_THREADS; ++i)

threads[i] = std::thread(threadMain);

for (i = 0; i < NUM_THREADS; ++i)

threads[i].join();

assert(global.load() == NUM_THREADS * NUM_ITERS);

// Same as above through `operator T`.

assert(global == NUM_THREADS * NUM_ITERS);

#endif

}