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Compilers implement a multiple-include optimization where they avoid preprocessing an included file if it is "properly guarded". Compilers differ as to what constitutes a "properly guarded" file. In particular, Microsoft Visual Studio does not recognize `#if !defined(GUARD)` for the optimization. This does not affect the correctness of using Fusion on Microsoft Visual Studio, but it will increase the time taken to build any project on this compiler. This commit changes all include guards to use `#ifndef`, but leaves all other `#if !defined` preprocessor directives that are not related to guarding a file. Co-authored-by: IncludeGuardian <hello@includeguardian.io>
50 lines
1.3 KiB
C++
50 lines
1.3 KiB
C++
/*=============================================================================
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Copyright (c) 2001-2011 Joel de Guzman
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Copyright (c) 2006 Dan Marsden
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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==============================================================================*/
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#ifndef BOOST_FUSION_VALUE_OF_IMPL_20060223_1905
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#define BOOST_FUSION_VALUE_OF_IMPL_20060223_1905
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#include <string>
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namespace example
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{
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struct example_struct_iterator_tag;
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template<typename Struct, int Pos>
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struct example_struct_iterator;
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}
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namespace boost { namespace fusion {
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namespace extension
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{
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template<typename Tag>
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struct value_of_impl;
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template<>
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struct value_of_impl<example::example_struct_iterator_tag>
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{
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template<typename Iterator>
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struct apply;
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template<typename Struct>
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struct apply<example::example_struct_iterator<Struct, 0> >
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{
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typedef std::string type;
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};
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template<typename Struct>
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struct apply<example::example_struct_iterator<Struct, 1> >
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{
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typedef int type;
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};
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};
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}
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}}
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#endif
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