зеркало из https://github.com/microsoft/STL.git
54 строки
1.4 KiB
C++
54 строки
1.4 KiB
C++
// xcall_once.h internal header
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// Copyright (c) Microsoft Corporation.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#pragma once
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#ifndef _XCALL_ONCE_H
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#define _XCALL_ONCE_H
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#include <yvals.h>
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#if _STL_COMPILER_PREPROCESSOR
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#pragma pack(push, _CRT_PACKING)
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#pragma warning(push, _STL_WARNING_LEVEL)
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#pragma warning(disable : _STL_DISABLED_WARNINGS)
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_STL_DISABLE_CLANG_WARNINGS
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#pragma push_macro("new")
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#undef new
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_STD_BEGIN
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// STRUCT once_flag
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struct once_flag { // opaque data structure for call_once()
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constexpr once_flag() noexcept : _Opaque(nullptr) {}
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once_flag(const once_flag&) = delete;
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once_flag& operator=(const once_flag&) = delete;
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void* _Opaque;
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};
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using _Execute_once_fp_t = int(__stdcall*)(void*, void*, void**);
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_CRTIMP2_PURE int __CLRCALL_PURE_OR_CDECL _Execute_once(
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once_flag& _Flag, _Execute_once_fp_t _Callback, void* _Pv) noexcept;
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template <class _Ty>
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union _Immortalizer_impl { // constructs _Ty, never destroys
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constexpr _Immortalizer_impl() noexcept : _Storage{} {}
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_Immortalizer_impl(const _Immortalizer_impl&) = delete;
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_Immortalizer_impl& operator=(const _Immortalizer_impl&) = delete;
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~_Immortalizer_impl() {
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// do nothing
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}
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_Ty _Storage;
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};
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_STD_END
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#pragma pop_macro("new")
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_STL_RESTORE_CLANG_WARNINGS
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#pragma warning(pop)
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#pragma pack(pop)
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#endif // _STL_COMPILER_PREPROCESSOR
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#endif // _XCALL_ONCE_H
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