Files
edk2-upstream/ShellPkg/Application/Shell/FileHandleInternal.h
Michael Kubacki 8472271dae ShellPkg: Replace include guards with #pragma once
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.

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>
2026-02-23 21:01:28 +00:00

56 lines
1.5 KiB
C

/** @file
internal worker functions for FileHandleWrappers to use
Copyright (c) 2009 - 2010, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#pragma once
/**
Move the cursor position one character backward.
@param[in] LineLength Length of a line. Get it by calling QueryMode
@param[in, out] Column Current column of the cursor position
@param[in, out] Row Current row of the cursor position
**/
VOID
MoveCursorBackward (
IN UINTN LineLength,
IN OUT UINTN *Column,
IN OUT UINTN *Row
);
/**
Move the cursor position one character forward.
@param[in] LineLength Length of a line.
@param[in] TotalRow Total row of a screen
@param[in, out] Column Current column of the cursor position
@param[in, out] Row Current row of the cursor position
**/
VOID
MoveCursorForward (
IN UINTN LineLength,
IN UINTN TotalRow,
IN OUT UINTN *Column,
IN OUT UINTN *Row
);
/**
Prints out each previously typed command in the command list history log.
When each screen is full it will pause for a key before continuing.
@param[in] TotalCols How many columns are on the screen
@param[in] TotalRows How many rows are on the screen
@param[in] StartColumn which column to start at
**/
VOID
PrintCommandHistory (
IN CONST UINTN TotalCols,
IN CONST UINTN TotalRows,
IN CONST UINTN StartColumn
);