[cmake] Simplify C++ standard enforcement using target_compile_features#8915
Merged
Conversation
Require C++20 directly on the `binaryen` target by adding `cxx_std_20` to `target_compile_features`. This enables CMake to automatically enforce that the compiler supports C++20 and propagates the requirement to all consumers linking against `binaryen`. Remove the manual `elseif(CMAKE_CXX_STANDARD LESS ...)` check and error message from `CMakeLists.txt` since CMake now natively handles standard validation and error reporting. Also remove the `if(NOT CMAKE_CXX_STANDARD)` condition around `set(CMAKE_CXX_STANDARD 20)` and its explanatory comment. The old comment suggested the conditional allowed embedding in parent projects with a higher default standard. However, variable assignments like `set(CMAKE_CXX_STANDARD 20)` in a subdirectory (via `add_subdirectory`) are strictly directory-scoped and do not leak into the parent project. Furthermore, with `target_compile_features` enforcing `cxx_std_20` on `binaryen`, any parent target linking against `binaryen` at a higher C++ standard (e.g., C++23) cleanly satisfies the feature requirement. Therefore, unconditionally setting `CMAKE_CXX_STANDARD 20` for internal Binaryen targets is completely safe and avoids inheriting incompatible standards (< 20) from parent projects.
sbc100
force-pushed
the
cmake-cxx-standard
branch
from
July 17, 2026 18:40
1e91c41 to
2daf1b8
Compare
tlively
approved these changes
Jul 17, 2026
tlively
left a comment
tlively
left a comment
Member
There was a problem hiding this comment.
Nice simplification! I'll just have to take the commit message's word that this is all correct.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Require C++20 directly on the
binaryentarget by addingcxx_std_20totarget_compile_features. This enables CMake toautomatically enforce that the compiler supports C++20 and propagates
the requirement to all consumers linking against
binaryen.Remove the manual
elseif(CMAKE_CXX_STANDARD LESS ...)check and errormessage from
CMakeLists.txtsince CMake now natively handles standardvalidation and error reporting.
Also remove the
if(NOT CMAKE_CXX_STANDARD)condition aroundset(CMAKE_CXX_STANDARD 20)and its explanatory comment. The oldcomment suggested the conditional allowed embedding in parent projects
with a higher default standard. However, variable assignments like
set(CMAKE_CXX_STANDARD 20)in a subdirectory (viaadd_subdirectory)are strictly directory-scoped and do not leak into the parent project.
Furthermore, with
target_compile_featuresenforcingcxx_std_20onbinaryen, any parent target linking againstbinaryenat a higher C++standard (e.g., C++23) cleanly satisfies the feature requirement.
Therefore, unconditionally setting
CMAKE_CXX_STANDARD 20for internalBinaryen targets is completely safe and avoids inheriting incompatible
standards (< 20) from parent projects.