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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: Tuan Ta, Moyang Wang
*/
#include <cstdlib>
#include <iostream>
#include <mutex>
#include <thread>
#include <vector>
//------------------------------------------------------------------------
// Create n threads, run them in parallel and wait for them in the master
// thread.
// Each child thread increments a shared variable m times
//------------------------------------------------------------------------
#define MAX_N_WORKER_THREADS 10
int main( int argc, const char* argv[] )
{
int n_worker_threads = 0;
// allocate all threads
std::vector< std::thread > threads;
// mutex to protect the shared variable
std::mutex my_mutex;
// variable shared among all threads
int shared_var = 0;
// number of steps each thread increments the shared_var
int nsteps = 1000;
for ( int tid = 0; tid < MAX_N_WORKER_THREADS; ++tid ) {
try {
threads.push_back( std::thread( [&] {
std::lock_guard<std::mutex> guard(my_mutex);
for ( int i = 0; i < nsteps; ++i )
shared_var++;
} ) );
} catch ( const std::system_error& err ) {
break;
}
n_worker_threads++;
}
// sync up all threads
for (int i = 0; i < n_worker_threads; ++i) {
threads[i].join();
}
// verify
if ( shared_var != n_worker_threads * nsteps || n_worker_threads < 1) {
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}
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