37 lines
1.1 KiB
Plaintext
37 lines
1.1 KiB
Plaintext
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// (C) Copyright David Abrahams 2001.
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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// See http://www.boost.org for most recent version including documentation.
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// Revision History
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// 09 Feb 01 Applied John Maddock's Borland patch Moving <true>
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// specialization to unspecialized template (David Abrahams)
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// 06 Feb 01 Created (David Abrahams)
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#ifndef SELECT_TYPE_DWA20010206_HPP
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# define SELECT_TYPE_DWA20010206_HPP
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namespace boost { namespace detail {
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// Template class if_true -- select among 2 types based on a bool constant expression
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// Usage:
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// typename if_true<(bool_const_expression)>::template then<true_type, false_type>::type
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// HP aCC cannot deal with missing names for template value parameters
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template <bool b> struct if_true
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{
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template <class T, class F>
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struct then { typedef T type; };
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};
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template <>
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struct if_true<false>
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{
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template <class T, class F>
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struct then { typedef F type; };
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};
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}}
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#endif // SELECT_TYPE_DWA20010206_HPP
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