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// Copyright 2015 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 <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <emscripten/emscripten.h>
#include <emscripten/console.h>
#define NUM_THREADS 3
#define TCOUNT 10
#define COUNT_LIMIT 12
int count = 0;
int thread_ids[3] = {0,1,2};
pthread_mutex_t count_mutex;
pthread_cond_t count_threshold_cv;
void *inc_count(void *t)
{
int i;
long my_id = (long)t;
for (i=0; i<TCOUNT; i++) {
pthread_mutex_lock(&count_mutex);
count++;
/*
Check the value of count and signal waiting thread when condition is
reached. Note that this occurs while mutex is locked.
*/
if (count == COUNT_LIMIT) {
pthread_cond_signal(&count_threshold_cv);
emscripten_outf("inc_count(): thread %ld, count = %d Threshold reached.\n", my_id, count);
}
emscripten_outf("inc_count(): thread %ld, count = %d, unlocking mutex\n", my_id, count);
pthread_mutex_unlock(&count_mutex);
/* Do some "work" so threads can alternate on mutex lock */
//sleep(1);
}
pthread_exit(NULL);
}
void *watch_count(void *t)
{
long my_id = (long)t;
emscripten_outf("Starting watch_count(): thread %ld\n", my_id);
/*
Lock mutex and wait for signal. Note that the pthread_cond_wait
routine will automatically and atomically unlock mutex while it waits.
Also, note that if COUNT_LIMIT is reached before this routine is run by
the waiting thread, the loop will be skipped to prevent pthread_cond_wait
from never returning.
*/
pthread_mutex_lock(&count_mutex);
while (count<COUNT_LIMIT) {
pthread_cond_wait(&count_threshold_cv, &count_mutex);
emscripten_outf("watch_count(): thread %ld Condition signal received.\n", my_id);
count += 125;
emscripten_outf("watch_count(): thread %ld count now = %d.\n", my_id, count);
}
pthread_mutex_unlock(&count_mutex);
pthread_exit(NULL);
}
int main (int argc, char *argv[])
{
int i, rc;
long t1=1, t2=2, t3=3;
pthread_t threads[3];
/* Initialize mutex and condition variable objects */
pthread_mutex_init(&count_mutex, NULL);
pthread_cond_init(&count_threshold_cv, NULL);
/* For portability, explicitly create threads in a joinable state */
pthread_create(&threads[0], NULL, watch_count, (void *)t1);
pthread_create(&threads[1], NULL, inc_count, (void *)t2);
pthread_create(&threads[2], NULL, inc_count, (void *)t3);
/* Wait for all threads to complete */
for (i=0; i<NUM_THREADS; i++) {
pthread_join(threads[i], NULL);
}
emscripten_outf("Main(): Waited on %d threads. Done.\n", NUM_THREADS);
/* Clean up and exit */
pthread_mutex_destroy(&count_mutex);
pthread_cond_destroy(&count_threshold_cv);
return 0;
}
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