| // (C) Copyright David Abrahams 2001. |
| // 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) |
| // |
| // See http://www.boost.org for most recent version including documentation. |
| |
| // Revision History |
| // 09 Feb 01 Applied John Maddock's Borland patch Moving <true> |
| // specialization to unspecialized template (David Abrahams) |
| // 06 Feb 01 Created (David Abrahams) |
| |
| #ifndef SELECT_TYPE_DWA20010206_HPP |
| # define SELECT_TYPE_DWA20010206_HPP |
| |
| namespace boost { namespace detail { |
| |
| // Template class if_true -- select among 2 types based on a bool constant expression |
| // Usage: |
| // typename if_true<(bool_const_expression)>::template then<true_type, false_type>::type |
| |
| // HP aCC cannot deal with missing names for template value parameters |
| template <bool b> struct if_true |
| { |
| template <class T, class F> |
| struct then { typedef T type; }; |
| }; |
| |
| template <> |
| struct if_true<false> |
| { |
| template <class T, class F> |
| struct then { typedef F type; }; |
| }; |
| }} |
| #endif // SELECT_TYPE_DWA20010206_HPP |