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Diffstat (limited to 'contrib/src/boost/utility/identity_type.hpp')
-rw-r--r-- | contrib/src/boost/utility/identity_type.hpp | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/contrib/src/boost/utility/identity_type.hpp b/contrib/src/boost/utility/identity_type.hpp new file mode 100644 index 0000000..4a1f6c4 --- /dev/null +++ b/contrib/src/boost/utility/identity_type.hpp @@ -0,0 +1,46 @@ + +// Copyright (C) 2009-2012 Lorenzo Caminiti +// Distributed under the Boost Software License, Version 1.0 +// (see accompanying file LICENSE_1_0.txt or a copy at +// http://www.boost.org/LICENSE_1_0.txt) +// Home at http://www.boost.org/libs/utility/identity_type + +/** @file +Wrap type expressions with round parenthesis so they can be passed to macros +even if they contain commas. +*/ + +#ifndef BOOST_IDENTITY_TYPE_HPP_ +#define BOOST_IDENTITY_TYPE_HPP_ + +#include <boost/type_traits/function_traits.hpp> + +/** +@brief This macro allows to wrap the specified type expression within extra +round parenthesis so the type can be passed as a single macro parameter even if +it contains commas (not already wrapped within round parenthesis). + +@Params +@Param{parenthesized_type, +The type expression to be passed as macro parameter wrapped by a single set +of round parenthesis <c>(...)</c>. +This type expression can contain an arbitrary number of commas. +} +@EndParams + +This macro works on any C++03 compiler (it does not use variadic macros). + +This macro must be prefixed by <c>typename</c> when used within templates. +Note that the compiler will not be able to automatically determine function +template parameters when they are wrapped with this macro (these parameters +need to be explicitly specified when calling the function template). + +On some compilers (like GCC), using this macro on abstract types requires to +add and remove a reference to the specified type. +*/ +#define BOOST_IDENTITY_TYPE(parenthesized_type) \ + /* must NOT prefix this with `::` to work with parenthesized syntax */ \ + boost::function_traits< void parenthesized_type >::arg1_type + +#endif // #include guard + |