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/*
* Copyright (c) 2018, Cornell University
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* Neither the name of Cornell University nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Author: Moyang Wang
*/
#include <pthread.h>
#include <cstdlib>
#include <iostream>
#include <mutex>
#include <vector>
//------------------------------------------------------------------------
// Test pthread_cond
//------------------------------------------------------------------------
// The master thread creates N threads, each of which waits on a
// condition variable of a signal to start. The master thread then set
// the signal and notifies all other threads to begin.
#define MAX_N_WORKER_THREADS 10
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t cv = PTHREAD_COND_INITIALIZER;
bool ready = false;
void* print_id( void* arg_vptr )
{
pthread_mutex_lock( &mutex );
long id = (long)arg_vptr;
while (!ready) {
pthread_cond_wait( &cv, &mutex );
}
// ...
std::cout << "thread " << id << '\n';
pthread_mutex_unlock( &mutex );
return nullptr;
}
void go()
{
pthread_mutex_lock( &mutex );
ready = true;
pthread_cond_broadcast( &cv );
pthread_mutex_unlock( &mutex );
}
int main( int argc, char* argv[] )
{
size_t n_worker_threads = 0;
std::vector< pthread_t > threads( MAX_N_WORKER_THREADS );
int ret = 0;
for ( size_t i = 0; i < MAX_N_WORKER_THREADS; i++ ){
ret = pthread_create( &threads[i], nullptr, print_id, (void*)i );
if (ret != 0) {
break;
}
n_worker_threads++;
}
std::cout << n_worker_threads << " threads ready to race...\n";
go();
for ( size_t i = 1; i < n_worker_threads; i++ ) {
pthread_join( threads[i], nullptr );
}
if (n_worker_threads < 1) {
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}
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