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// Copyright 2018 The Emscripten Authors. All rights reserved.
// Emscripten is available under two separate licenses, the MIT license and the
// University of Illinois/NCSA Open Source License. Both these licenses can be
// found in the LICENSE file.
#include <assert.h>
#include <pthread.h>
#include <emscripten.h>
#include <emscripten/threading.h>
#include <math.h>
#include <stdio.h>
volatile int threadStarted = 0;
volatile int timeReceived = 0;
volatile double mainThreadTime;
void wait(volatile int *address) {
int state = emscripten_atomic_load_u32((void*)address);
while (state == 0) {
state = emscripten_atomic_load_u32((void*)address);
}
}
void wake(volatile int *address) {
emscripten_atomic_store_u32((void*)address, 1);
}
void *thread_main(void *arg) {
wake(&threadStarted);
wait(&timeReceived);
double pthreadTime = emscripten_get_now();
double timeDifference = pthreadTime - mainThreadTime;
printf("Time difference between pthread and main thread is %f msecs.\n", timeDifference);
// The time difference here should be well less than 1 msec, but test against
// 200msecs to be super-sure.
assert(fabs(timeDifference) < 200);
emscripten_force_exit(0);
return 0;
}
void busy_sleep(double msecs) {
double end = emscripten_get_now() + msecs;
while (emscripten_get_now() < end) {
// busy loop
}
}
int main()
{
// Cause a one second delay between main() and pthread start that might have a
// chance to drift the wallclocks on emscripten_get_now().
busy_sleep(1000);
pthread_t thread;
pthread_create(&thread, NULL, thread_main, NULL);
wait(&threadStarted);
mainThreadTime = emscripten_get_now();
wake(&timeReceived);
emscripten_exit_with_live_runtime();
}
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