Can you give examples of resources managed using RAII, besides smart pointers?

RAII (Resource Acquisition Is Initialization) is an idiom in C++ that ties the lifetime of a resource to the lifetime of an object.

Besides smart pointers, RAII is often used to manage:

• File descriptors: a class opens a file in its constructor and closes it in its destructor.
• Mutexes and locks: an object locks a resource upon creation and unlocks it upon destruction, for example, std::lock_guard.
• Network connections: opening a connection in the constructor and closing it in the destructor.
• Manually allocated memory: wrappers for dynamic memory allocation and deallocation.

Example with mutex locking:

std::mutex mtx;

void func() {
    std::lock_guard<std::mutex> lock(mtx); // locks the mutex
    // critical section
} // upon exiting the function, lock_guard is destroyed and the mutex is unlocked

This approach guarantees resource release even in case of exceptions.