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a536e5d699
Replace traditional `#ifndef`/`#define`/`#endif` include guards with
`#pragma` once.
`#pragma once` is a widely supported preprocessor directive that
prevents header files from being included multiple times. It is
supported by all toolchains used to build edk2: GCC, Clang/LLVM, and
MSVC.
Note: Headers taken directly from external projects, such as those
in OvmfPkg/Include/IndustryStandard/Xen/ were not modified since they
may be periodically re-synced and do not follow other edk2 coding
stadards.
Compared to macro-based include guards, `#pragma once`:
- Eliminates the risk of macro name collisions or copy/paste errors
where two headers inadvertently use the same guard macro.
- Eliminate inconsistency in the way include guard macros are named
(e.g., some files use `__FILE_H__`, others use `FILE_H_`, etc.).
- Reduces boilerplate (three lines replaced by one).
- Avoids polluting the macro namespace with guard symbols.
- Can improve build times as the preprocessor can skip re-opening the
file entirely, rather than re-reading it to find the matching
`#endif` ("multiple-include optimization").
- Note that some compilers may already optimize traditional include
guards, by recognzining the idiomatic pattern.
This change is made acknowledging that overall portability of the
code will technically be reduced, as `#pragma once` is not part of the
C/C++ standards.
However, this is considered acceptable given:
1. edk2 already defines a subset of supported compilers in
BaseTools/Conf/tools_def.template, all of which have supported
`#pragma once` for over two decades.
2. There have been concerns raised to the project about inconsistent
include guard naming and potential macro collisions.
Approximate compiler support dates:
- MSVC: Supported since Visual C++ 4.2 (1996)
- GCC: Supported since 3.4 (2004)
(http://gnu.ist.utl.pt/software/gcc/gcc-3.4/changes.html)
- Clang (LLVM based): Since initial release in 2007
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
53 lines
1.1 KiB
C
53 lines
1.1 KiB
C
/** @file
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Utility functions for serializing (persistently storing) and deserializing
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OVMF's platform configuration.
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Copyright (C) 2014, Red Hat, Inc.
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#pragma once
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#include <Base.h>
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//
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// This structure participates in driver configuration. It does not
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// (necessarily) reflect the wire format in the persistent store.
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//
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#pragma pack(1)
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typedef struct {
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//
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// preferred graphics console resolution when booting
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//
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UINT32 HorizontalResolution;
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UINT32 VerticalResolution;
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} PLATFORM_CONFIG;
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#pragma pack()
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//
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// Please see the API documentation near the function definitions.
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//
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EFI_STATUS
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EFIAPI
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PlatformConfigSave (
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IN PLATFORM_CONFIG *PlatformConfig
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);
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EFI_STATUS
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EFIAPI
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PlatformConfigLoad (
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OUT PLATFORM_CONFIG *PlatformConfig,
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OUT UINT64 *OptionalElements
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);
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//
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// Feature flags for OptionalElements.
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//
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#define PLATFORM_CONFIG_F_GRAPHICS_RESOLUTION BIT0
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#define PLATFORM_CONFIG_F_DOWNGRADE BIT63
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extern CHAR16 mVariableName[];
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extern CHAR16 mHiiFormName[];
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