Objects Own Resources (RAII)

Make sure that objects own resources. This principle is also known as “resource acquisition is initialization” or “RAII.”


Pass every “new” object as a constructor argument to another named object that owns it (almost always unique_ptr).

void f() {  
    unique_ptr<widget> p( new widget() );  
    my_class x( new widget() );  
    // ...  
} // automatic destruction and deallocation for both widget objects  
  // automatic exception safety, as if "finally { p->dispose(); x.w.dispose(); }"  

Always immediately pass any new resource to another object that owns it.

void g() {  
    other_class y( OpenFile() );  
    // ...  
} // automatic closing and release for file resource  
  // automatic exception safety, as if "finally { y.file.dispose(); }"  

See Also

Welcome Back to C++
C++ Language Reference
C++ Standard Library