What are some examples of semaphore usage in C++?

What are some examples of semaphore usage in C++?

Semaphores are used in C++ for controlling access to shared resources in concurrent programming. Would you like to see a code example?

Yes, please provide a code example.

Here's a simple example using the C++ standard library:

#include <iostream>
#include <thread>
#include <semaphore.h>

std::binary_semaphore sem(1); // Initialize semaphore with 1

void accessResource(int id) {
    sem.acquire(); // Wait for the semaphore
    std::cout << "Thread " << id << " is accessing the resource." << std::endl;
    std::this_thread::sleep_for(std::chrono::seconds(1)); // Simulate resource access
    std::cout << "Thread " << id << " is done accessing the resource." << std::endl;
    sem.release(); // Release the semaphore
}

int main() {
    std::thread t1(accessResource, 1);
    std::thread t2(accessResource, 2);
    t1.join();
    t2.join();
    return 0;
}

What does this code do?

This code creates two threads that attempt to access a shared resource. The semaphore ensures that only one thread can access the resource at a time, preventing race conditions.