MutexTryLock.cpp

/* TOPIC: std::mutex::try_lock() On Mutex In C++11 Threading

0. try_lock() Tries to lock the mutex. Returns immediately. On successful lock acquisition returns true otherwise returns false.
1. If try_lock() is not able to lock mutex, then it doesn't get blocked that's why it is called non-blocking.
2. If try_lock is called again by the same thread which owns the mutex, the behavior is undefined.
   It is a dead lock situation with undefined behavior. (if you want to be able to lock the same mutex by same thread more than one time the go for recursive_mutex)

There are so many try_lock function
1. std::try_lock
2. std::mutex::try_lock
3. std::shared_lock::try_lock
4. std::timed_mutex::try_lock
5. std::unique_lock::try_lock
6. std::shared_mutex::try_lock
7. std::recursive_mutex::try_lock
8. std::shared_timed_mutex::try_lock
9. std::recursive_timed_mutex::try_lock */

#include<iostream>
#include<mutex>
#include<thread>

using namespace std;
int counter = 0;
std::mutex mx;

void IncreaseCounter100000Times()
{
    for (int i = 0; i < 100000; i++)
    {
       if(mx.try_lock())
            ++counter;
        mx.unlock();
    }  
}

int main()
{
    std::thread t1(IncreaseCounter100000Times);
    std::thread t2(IncreaseCounter100000Times);

    t1.join();
    t2.join();

    cout<<"Counter could increase up to : "<<counter<<endl;
    return 0;
}

//compile: g++ -std=c++11 MutexTryLock.cpp -pthread
//Output: Counter could increase up to : 170463