objects-own-resources-raii.md

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Objects Own Resources (RAII) | Microsoft Docs		11/04/2016			cpp-language		article	C++	f86b484e-5a27-4c3b-a92a-dfaa5dd6d93a	4	mikeblome	mblome	ghogen

Objects Own Resources (RAII)

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

Example

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