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/*
* Berkeley Lab Checkpoint/Restart (BLCR) for Linux is Copyright (c)
* 2003, The Regents of the University of California, through Lawrence
* Berkeley National Laboratory (subject to receipt of any required
* approvals from the U.S. Dept. of Energy). All rights reserved.
*
* Portions may be copyrighted by others, as may be noted in specific
* copyright notices within specific files.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* $Id: pthread_counting.c,v 1.5 2007/05/07 19:41:46 phargrov Exp $
*/
#include <time.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <pthread.h>
#include <errno.h>
#include <inttypes.h>
#define THREADS 3
static int limit = 120; /* default */
static int count = 0;
static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
static void delay(void)
{
struct timespec ts = {tv_sec: 1, tv_nsec: 0};
int rc;
do {
rc = nanosleep(&ts, &ts);
} while ((rc <0) && (errno == EINTR) && (ts.tv_sec || ts.tv_nsec));
}
static void advance(void)
{
pthread_mutex_lock(&lock);
count++;
pthread_cond_broadcast(&cond);
pthread_mutex_unlock(&lock);
}
static void wait_for(int i)
{
pthread_mutex_lock(&lock);
while ((count % THREADS) != i) {
pthread_cond_wait(&cond, &lock);
}
pthread_mutex_unlock(&lock);
}
static void * thread(void * arg)
{
int id = (int)(uintptr_t)arg;
int local;
do {
wait_for(id);
local = count;
printf("Thread %d says count = %d\n", id, local);
delay();
advance();
} while (local < limit);
return NULL; /* Not reached */
}
int main(int argc, char *argv[])
{
pthread_t th[THREADS];
int i;
printf("Starting main process w/ pid %d\n", (int)getpid());
if (argc > 1) {
limit = (i = atoi(argv[1])) > 0 ? i : limit;
}
// Start one or more threads
for (i = 1; i < THREADS; ++i) {
pthread_create(&th[i], NULL, thread, (void *)(uintptr_t)i);
}
thread((void *)0);
return 0;
}
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