#include <iostream>
#include <mutex>
#include <thread>
#include <stdexcept> // For runtime_error

using namespace std ;

mutex global_mutex ; // A global mutex to protect shared resources

void protected_function()
{
    cout << "Attempting to acquire lock..." << endl;
    // lock_guard acquires the lock in its constructor
    // and automatically releases it in its destructor when it goes out of scope.
    lock_guard<mutex> lock(global_mutex);
    cout << "Lock acquired." << endl;
    // Simulate some work that might throw an exception

    cout << "Work completed (this line won't be reached if exception is thrown)." << endl;
} // lock_guard goes out of scope here, releasing the mutex (even on exception)

int main()
{
		lock_guard<mutex> lock(global_mutex)  ;
        thread t1( protected_function );
        thread t2( protected_function );

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



    return 0;
}