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#include <iostream>
#include <unistd.h>
#include <pthread.h>
#define noinline __attribute__((noinline))
#define NUM_ACCUMULATORS 4
volatile long sum;
pthread_mutex_t sum_lock = PTHREAD_MUTEX_INITIALIZER;
/* Accumulate into a global variable. */
// Will be livepatched;
void noinline accumulate(long x)
{
if (pthread_mutex_lock(&sum_lock) != 0) {
abort();
}
sum += x;
if (pthread_mutex_unlock(&sum_lock) != 0) {
abort();
}
}
void *accumulator(void* x)
{
for (long i = 0; i < 100000000L; i++) {
accumulate(i);
}
return NULL;
}
int main(void)
{
pthread_t threads[NUM_ACCUMULATORS];
for (int i = 0; i < NUM_ACCUMULATORS; i++) {
if (pthread_create(&threads[i], NULL, accumulator, NULL) != 0) {
abort();
}
}
for (int i = 0; i < NUM_ACCUMULATORS; i++) {
if (pthread_join(threads[i], NULL) != 0) {
abort();
}
}
printf("sum = %ld\n", sum);
return 0;
}
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