RAII

C++ programs frequently deal with system resources like memory, file and socket handles, shared memory segments, mutexes, and so on. There are well-defined primitives, some from the C Standard Library and many more from the native systems programming interfaces, which are used to request and relinquish these resources. Failing to guarantee the release of acquired resources can cause grave problems to an application's performance and correctness.

The destructor of a C++ object on the stack is automatically invoked during stack unwinding. The unwinding happens when a scope is exited due to control reaching the end of the scope, or by executing return, goto, break, or continue. A scope is also exited as a result of an exception being thrown. In either case, the destructor is guaranteed to be called. This guarantee is limited to C++ objects on the stack. It does not apply to C++ objects on the heap because they are not associated with a lexical scope. Furthermore, it does not apply...