Reference Property Map

##

    template <typename KeyType, typename ValueType>
    class ref_property_map

This property map wraps a reference to some particular object, and returns that reference whenever a key object is input.

### Where Defined

`boost/property_map.hpp`

### Model of

Lvalue Property Map

### Associated Types

Type | Description
--- | ---
`boost::property_traits<ref_property_map>::value_type` | This type is the `ValueType` with which the template instantiated.
`boost::property_traits<ref_property_map>::key_type` | This type is the `KeyType` with which the template instantiated.
`boost::property_traits<ref_property_map>::category` | This type is `boost::lvalue_property_map_tag`.

### Member Functions

Member | Description
--- | ---
`ref_property_map(ValueType& v)` | The constructor for ref_property_map is provided the reference that the property map will return when queried.
`ref_property_map(const ref_property_map& x)` | Copy constructor.
`ValueType& operator[](KeyType const&) const` | Returns the contained reference.