CryptoPkg: Replace include guards with #pragma once

2026-02-23T21:01:28+00:00

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. Does not include updates to OpenSSL generated header files checked into the repo. Those in `CryptoPkg\Library\OpensslLib\OpensslGen\`. 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

CryptoPkg: Add Null instance of the BaseCryptLib class

2019-10-24T01:37:19+00:00

https://bugzilla.tianocore.org/show_bug.cgi?id=2257 Add a Null instance of the BaseCryptLib class. This lib instance can be used as a template for new implementations of the BaseCryptLib class and can also be used to reduce CI build times for build checks that depend on the BaseCryptLib class. Cc: Jian J Wang Cc: Xiaoyu Lu Signed-off-by: Michael D Kinney Reviewed-by: Jian J Wang

Tianocore/edk2.git/CryptoPkg/Library/BaseCryptLibNull/InternalCryptLib.h, branch master

CryptoPkg: Replace include guards with #pragma once

CryptoPkg: Add Null instance of the BaseCryptLib class