42 lines
1.4 KiB
C++
42 lines
1.4 KiB
C++
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#ifndef BOOST_CONTRACT_DETAIL_STATIC_LOCAL_VAR_HPP_
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#define BOOST_CONTRACT_DETAIL_STATIC_LOCAL_VAR_HPP_
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// Copyright (C) 2008-2018 Lorenzo Caminiti
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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 a copy at http://www.boost.org/LICENSE_1_0.txt).
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// See: http://www.boost.org/doc/libs/release/libs/contract/doc/html/index.html
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namespace boost { namespace contract { namespace detail {
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// This is used to hold the state of this library (already checking assertions,
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// failure handers, mutexes, etc.). Local static variables are used instead of
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// global or class-level static variables to avoid ODR errors when this library
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// is used as header-only.
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// Use T's default constructor to init the local var.
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template<typename Tag, typename T>
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struct static_local_var {
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static T& ref() {
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static T data;
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return data;
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}
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};
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// Use `init` param to init local var (Init same as or convertible to T).
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// NOTE: Template specializations could be used to program both this and the
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// template above together but some pre-C++11 compilers give errors (e.g., Clang
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// without -std=c++11), plus the `_init` postfix is more readable at call site.
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template<typename Tag, typename T, typename Init, Init init>
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struct static_local_var_init {
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static T& ref() {
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static T data = init;
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return data;
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}
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};
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} } } // namespace
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#endif // #include guard
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