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// Copyright 2016 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 <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <emscripten/threading.h>
#include <emscripten/emscripten.h>
#include <assert.h>
#include <math.h>
#include <limits.h>
#define NUM_THREADS 8
unsigned int futexVal = 0;
unsigned int numAwoken = 0;
pthread_t wakingThread;
pthread_t waitingThreads[NUM_THREADS];
void *WakingThread(void *arg)
{
// Wake all threads waiting for the futex address
emscripten_atomic_store_u32(&futexVal, 1);
emscripten_futex_wake(&futexVal, INT_MAX);
pthread_exit(0);
}
void *WaitingThread(void *arg)
{
// Last waiting thread creates the waking thread - this simplifies mutual synchronization needs
if ((long)arg == NUM_THREADS-1)
{
pthread_create(&wakingThread, 0, WakingThread, 0);
}
// Each waiting thread waits until wake thread changes the value at the wait address
while(emscripten_atomic_load_u32(&futexVal) == 0)
{
emscripten_futex_wait(&futexVal, 0, INFINITY);
}
// Tally up the number of awoken threads - last one to wake up signals test success
uint32_t old = emscripten_atomic_add_u32(&numAwoken, 1);
if (old + 1 == NUM_THREADS)
{
emscripten_force_exit(0);
}
return 0;
}
int main()
{
for(int i = 0; i < NUM_THREADS; ++i)
{
pthread_create(waitingThreads+i, 0, WaitingThread, (void*)i);
}
emscripten_exit_with_live_runtime();
}
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