ba87515fea
Currently, the library-internal feature test macros are only defined if the feature is not available, and always have the prefix `_LIBCPP_HAS_NO_`. This patch changes that, so that they are always defined and have the prefix `_LIBCPP_HAS_` instead. This changes the canonical use of these macros to `#if _LIBCPP_HAS_FEATURE`, which means that using an undefined macro (e.g. due to a missing include) is diagnosed now. While this is rather unlikely currently, a similar change in `<__configuration/availability.h>` caught a few bugs. This also improves readability, since it removes the double-negation of `#ifndef _LIBCPP_HAS_NO_FEATURE`. The current patch only touches the macros defined in `<__config>`. If people are happy with this approach, I'll make a follow-up PR to also change the macros defined in `<__config_site>`.
51 lines
1.5 KiB
C++
51 lines
1.5 KiB
C++
// -*- C++ -*-
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//===---------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===---------------------------------------------------------------------===//
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#ifndef _LIBCPP___FWD_STRING_VIEW_H
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#define _LIBCPP___FWD_STRING_VIEW_H
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#include <__config>
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#include <__fwd/string.h>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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template <class _CharT, class _Traits = char_traits<_CharT> >
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class _LIBCPP_TEMPLATE_VIS basic_string_view;
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typedef basic_string_view<char> string_view;
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#if _LIBCPP_HAS_CHAR8_T
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typedef basic_string_view<char8_t> u8string_view;
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#endif
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typedef basic_string_view<char16_t> u16string_view;
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typedef basic_string_view<char32_t> u32string_view;
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#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
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typedef basic_string_view<wchar_t> wstring_view;
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#endif
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// clang-format off
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template <class _CharT, class _Traits>
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class _LIBCPP_PREFERRED_NAME(string_view)
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#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
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_LIBCPP_PREFERRED_NAME(wstring_view)
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#endif
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#if _LIBCPP_HAS_CHAR8_T
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_LIBCPP_PREFERRED_NAME(u8string_view)
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#endif
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_LIBCPP_PREFERRED_NAME(u16string_view)
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_LIBCPP_PREFERRED_NAME(u32string_view)
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basic_string_view;
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// clang-format on
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___FWD_STRING_VIEW_H
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