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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.
*
* Authors: Moyang Wang
*/
#include <condition_variable>
#include <iostream>
#include <mutex>
#include <thread>
#include <vector>
//------------------------------------------------------------------------
// Test std::condition_variable
//------------------------------------------------------------------------
// 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
std::mutex mtx;
std::condition_variable cv;
bool ready = false;
void print_id( size_t id )
{
std::unique_lock<std::mutex> lck(mtx);
while (!ready)
cv.wait(lck);
// ...
std::cout << "thread " << id << '\n';
}
void go()
{
std::unique_lock<std::mutex> lck(mtx);
ready = true;
cv.notify_all();
}
int main( int argc, char* argv[] )
{
size_t n_worker_threads = 0;
std::vector< std::thread > threads;
for ( size_t i = 0; i < MAX_N_WORKER_THREADS; i++ ) {
try {
threads.push_back( std::thread( print_id, i ) );
} catch ( const std::system_error& err ) {
break;
}
n_worker_threads++;
}
std::cout << n_worker_threads << " threads ready to race...\n";
go(); // go!
for (int i = 0; i < n_worker_threads; ++i) {
threads[i].join();
}
// if there is no timeout (i.e., threads are all waken up properly, this
// test always succeeds)
return EXIT_SUCCESS;
}
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