What are the different methods of ensuring synchronization of processes or threads?

Various methods and mechanisms are used for synchronizing processes or threads in C/C++:

• Mutexes — ensure mutual exclusion so that only one thread can execute a critical section.
• Semaphores — limit the number of threads executing a certain section of code simultaneously.
• Condition variables — allow threads to wait for a specific event to occur.
• Barriers — synchronize a group of threads, making them wait for each other.
• Atomic operations — operations that are performed without interruption, used for simple synchronizations.

Example of using a mutex in C++11:

#include <mutex>
std::mutex mtx;

void critical_section() {
    mtx.lock();
    // code that should be executed by only one thread
    mtx.unlock();
}

Or with RAII:

void critical_section() {
    std::lock_guard<std::mutex> lock(mtx);
    // safe access to shared resources
}