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The MPL Reference Manual: clear
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clear

Synopsis

template<
      typename Sequence
    >
struct clear
{
    typedef unspecified type;
};

Description

Returns an empty sequence concept-identical to Sequence.

Parameters

Parameter Requirement Description
Sequence Extensible Sequence or Extensible Associative Sequence A sequence to get an empty "copy" of.

Expression semantics

For any Extensible Sequence or Extensible Associative Sequence s:

typedef clear::type t;
Return type:

Extensible Sequence or Extensible Associative Sequence.
Semantics:

Equivalent to

typedef erase< s, begin::type, end::type >::type t;
Postcondition:

empty::value == true.

Complexity

Amortized constant time.

Example

typedef vector_c odds;
typedef clear::type nothing;

BOOST_MPL_ASSERT(( empty ));
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Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams
Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)