/usr/include/boost/utility/declval.hpp is in libboost1.58-dev 1.58.0+dfsg-5ubuntu3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 | // declval.hpp -------------------------------------------------------------//
// Copyright 2010 Vicente J. Botet Escriba
// Distributed under the Boost Software License, Version 1.0.
// See http://www.boost.org/LICENSE_1_0.txt
#ifndef BOOST_UTILITY_DECLVAL_HPP
#define BOOST_UTILITY_DECLVAL_HPP
#include <boost/config.hpp>
//----------------------------------------------------------------------------//
#include <boost/type_traits/add_rvalue_reference.hpp>
//----------------------------------------------------------------------------//
// //
// C++03 implementation of //
// 20.2.4 Function template declval [declval] //
// Written by Vicente J. Botet Escriba //
// //
// 1 The library provides the function template declval to simplify the
// definition of expressions which occur as unevaluated operands.
// 2 Remarks: If this function is used, the program is ill-formed.
// 3 Remarks: The template parameter T of declval may be an incomplete type.
// [ Example:
//
// template <class To, class From>
// decltype(static_cast<To>(declval<From>())) convert(From&&);
//
// declares a function template convert which only participates in overloading
// if the type From can be explicitly converted to type To. For another example
// see class template common_type (20.9.7.6). -end example ]
//----------------------------------------------------------------------------//
namespace boost {
template <typename T>
typename add_rvalue_reference<T>::type declval() BOOST_NOEXCEPT; // as unevaluated operand
} // namespace boost
#endif // BOOST_UTILITY_DECLVAL_HPP
|