Table of Contents
Concurrency in C and C++ allows multiple threads to execute simultaneously, improving performance and resource utilization. Proper synchronization is essential to prevent data races and ensure program correctness. This article explores common synchronization techniques with practical examples.
Mutexes
Mutexes are used to protect shared resources by allowing only one thread to access the resource at a time. In C++, std::mutex from the <mutex> header provides a simple interface for mutual exclusion.
Example:
std::mutex mtx;
To lock and unlock:
mtx.lock();
mtx.unlock();
Semaphores
Semaphores control access to a resource by maintaining a counter. They can allow multiple threads to access a resource simultaneously up to a limit. POSIX semaphores are commonly used in C.
Example:
#include <semaphore.h>
Initialize:
sem_t sem;
Usage:
sem_wait(&sem); and sem_post(&sem);
Atomic Operations
Atomic operations ensure that read-modify-write sequences are completed without interruption. In C++, <atomic> provides atomic types and functions.
Example:
#include <atomic>
Declaration:
std::atomic counter(0);
Increment:
counter.fetch_add(1);
Conclusion
Synchronization techniques like mutexes, semaphores, and atomic operations are essential for managing concurrency in C and C++. Choosing the appropriate method depends on the specific requirements of the application and the level of control needed.