598bfd3f
 Hu Chunming
提交_GLIBCXX_USE_CX...
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/// @file
// Copyright (c) 2009-2020 Vladimir Batov.
// Use, modification and distribution are subject to the Boost Software License,
// Version 1.0. See http://www.boost.org/LICENSE_1_0.txt.
#ifndef BOOST_MAKE_DEFAULT_HPP
#define BOOST_MAKE_DEFAULT_HPP
namespace boost
{
/// @details A considerable number of libraries require an instance of a class
/// provided (storage created and initialized). For example,
/// @code
/// Type result;
/// ...
/// istream >> result;
/// @endcode
/// In generic code that results in the Default Constructibility requirement imposed
/// on every type 'Type' to be used with the respective code. Inevitably, that requirement
/// a) either excludes all the classes that for various reasons do not meet that requirement or
/// b) imposes certain (not necessarily desirable) design/implementation onto respective classes.
///
/// Deployment of boost::make_default() eliminates the Default Constructibility requirement with
/// @code
/// Type result = boost::make_default<Type>();
/// ...
/// istream >> result;
/// @endcode
/// Classes with no default constructor can now be included via a boost::make_default() specialization:
/// @code
/// namespace boost
/// {
/// template<> inline Type make_default<Type>() { return Type(parameters); }
/// }
/// @endcode
template<typename T> T make_default() { return T(); }
}
#endif // BOOST_MAKE_DEFAULT_HPP
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