QuantLib
A free/open-source library for quantitative finance
Reference manual - version 1.20
Public Member Functions | List of all members
Disposable< T > Class Template Reference

generic disposable object with move semantics More...

#include <ql/utilities/disposable.hpp>

Inherits T.

Public Member Functions

 Disposable (T &t)
 
 Disposable (const Disposable< T > &t)
 
Disposable< T > & operator= (const Disposable< T > &t)
 

Detailed Description

template<class T>
class QuantLib::Disposable< T >

generic disposable object with move semantics

This class can be used for returning a value by copy. It relies on the returned object exposing a swap(T&) method through which the copy constructor and assignment operator are implemented, thus resulting in actual move semantics. Typical use of this class is along the following lines:

Disposable<Foo> bar(Integer i) {
Foo f(i*2);
return f;
}
Warning:
In order to avoid copies in code such as shown above, the conversion from T to Disposable<T> is destructive, i.e., it does not preserve the state of the original object. Therefore, it is necessary for the developer to avoid code such as
Disposable<Foo> bar(Foo& f) {
return f;
}

which would likely render the passed object unusable. The correct way to obtain the desired behavior would be:

Disposable<Foo> bar(Foo& f) {
Foo temp = f;
return temp;
}