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mutex.cpp
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mutex.cpp
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/*
# mutex
Only allows one thread to enter the critical zone.
This is an artificial example: the more restricted and efficient atomic would be a better fit.
http://stackoverflow.com/questions/6837699/are-mutex-lock-functions-sufficient-without-volatile
*/
#include "common.hpp"
#if __cplusplus >= 201103L
long int global = 0;
std::mutex mutex;
void threadMain() {
for (int i = 0; i < NUM_ITERS; ++i) {
#ifndef FAIL
mutex.lock();
#endif
global++;
#ifndef FAIL
mutex.unlock();
#endif
}
}
#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();
if (global != NUM_OPS) {
printf("fraction of errors = %f\n", (1.0 - (double)global/NUM_OPS));
assert(false);
}
#endif
}