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

using namespace std ;

recursive_mutex myRecursiveMutex;

void recursiveFunction(int depth)
{
    unique_lock<recursive_mutex> lock(myRecursiveMutex); // Acquires the lock
    cout << "Thread " << this_thread::get_id() << " entered recursiveFunction at depth " << depth << endl;

    if (depth > 0) {
        recursiveFunction(depth - 1); // Recursive call, re-acquires the lock
    }

    cout << "Thread " << this_thread::get_id() << " exiting recursiveFunction at depth " << depth << endl;
} // Lock is released here (when unique_lock goes out of scope)

int main()
{
    thread t1(recursiveFunction, 2);
    t1.join();
    return 0;
}