The MPL Reference Manual: deref

deref

Synopsis

template<
      typename Iterator
    >
struct deref
{
    typedef unspecified type;
};

Description

Dereferences an iterator.

Header

#include <boost/mpl/deref.hpp>

Parameters

Parameter	Requirement	Description
`Iterator`	Forward Iterator	The iterator to dereference.

Expression semantics

For any Forward Iterators iter:

typedef deref<iter>::type t;

Return type: A type.

Precondition: iter is dereferenceable.

Semantics:

Return type:	A type.
Precondition:	`iter` is dereferenceable.
Semantics:	`t` is identical to the element referenced by `iter`. If `iter` is a user-defined iterator, the library-provided default implementation is equivalent to typedef iter::type t;

t is identical to the element referenced by iter. If iter is a user-defined iterator, the library-provided default implementation is equivalent to

typedef iter::type t;

Complexity

Amortized constant time.

Example

typedef vector<char,short,int,long> types;
typedef begin<types>::type iter;

BOOST_MPL_ASSERT(( is_same< deref<iter>::type, char > ));

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