ecl::ReferenceWrapper< T > Class Template Reference

Provides a wrapper which allows the original object to be passed like a reference. More...

#include <references.hpp>

Public Types
typedef T	type

Public Member Functions
	operator T& () const
	Convenience operator for converting to the underlying reference directly. More...
T *	pointer () const
	Accessor to a pointer to the original instance. More...
T &	reference () const
	Accessor to the reference of the original instance. More...
	ReferenceWrapper (T &t)
	Constructs the wrapper around the supplied object instance. More...
virtual	~ReferenceWrapper ()

Private Attributes
T *	obj_ptr

Detailed Description

template<typename T>
class ecl::ReferenceWrapper< T >

Provides a wrapper which allows the original object to be passed like a reference.

This class wraps the supplied object, storing it as a pointer and allowing it to be passed like a regular object. By itself, this is not terribly useful, but in combination with the ref/cref functions and also the is_reference_wrapper trait, it allows things like functions and function objects to be easily manipulated.

Note: reference wrappers might seem a bit redundant - why do we need them? The following case illustrates a desired usage scenario.

class A {
public:
    template <typename T>
    void f(T i) { cout << "Not a reference input" << endl; }
 
    template <typename T>
    void f(T &i) { cout << "A reference input" << endl; }
}

Unfortunately, when you come to call this function, you'll get an ambiguity error.

In these situations you can use a simple function call (not ref) and pass in this reference wrapper:

class A {
public:
    template <typename T>
    void f(const T &t) {
        if ( is_reference_wrapper<T> ) {
            // do something for references
        } else {
            // do something for non-references
        }
    }
}

Template Parameters

T	: the type of object this class is wrapping.

Definition at line 91 of file references.hpp.

Member Typedef Documentation

type

template<typename T >

typedef T ecl::ReferenceWrapper< T >::type

Convenient handle to the reference wrapper's base type.

Definition at line 94 of file references.hpp.

Constructor & Destructor Documentation

ReferenceWrapper()

template<typename T >

ecl::ReferenceWrapper< T >::ReferenceWrapper ( T &  t )

inline

Constructs the wrapper around the supplied object instance.

Constructs the wrapper around the supplied object instance.

Parameters

t	: the object instance.

Definition at line 103 of file references.hpp.

~ReferenceWrapper()

template<typename T >

virtual ecl::ReferenceWrapper< T >::~ReferenceWrapper ( )

inlinevirtual

Definition at line 105 of file references.hpp.

Member Function Documentation

operator T&()

template<typename T >

ecl::ReferenceWrapper< T >::operator T& ( ) const

inline

Convenience operator for converting to the underlying reference directly.

When used where the underlying reference is expected, this automatically handles the conversion.

Returns

T& : the returned reference to the wrapped object.

Definition at line 115 of file references.hpp.

pointer()

template<typename T >

T* ecl::ReferenceWrapper< T >::pointer ( ) const

inline

Accessor to a pointer to the original instance.

Returns a pointer to the wrapped object.

Returns

T& : the returned pointer to the wrapped object.

Definition at line 133 of file references.hpp.

reference()

template<typename T >

T& ecl::ReferenceWrapper< T >::reference ( ) const

inline

Accessor to the reference of the original instance.

Returns a reference to the wrapped object.

Returns

T& : the returned reference to the wrapped object.

Definition at line 124 of file references.hpp.

Member Data Documentation

obj_ptr

template<typename T >

T* ecl::ReferenceWrapper< T >::obj_ptr

private

Definition at line 136 of file references.hpp.

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The documentation for this class was generated from the following file:

• references.hpp