Move externs into "impl" category #475
Merged
Conversation
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
Scottj1s
approved these changes
Jan 16, 2020
alvinhochun
added a commit
to alvinhochun/cppwinrt
that referenced
this pull request
Dec 16, 2022
Weak symbols on mingw-w64 target with GCC and the GNU linker is a bit broken for the intended use. When using the .weak + .set combo and the referenced symbol is undefined, LD does not produce an error but instead treat the referenced symbol like a weak symbol. This can happen if some of the link library flags is missing. The output executables will crash on run time. This change makes the WINRT_IMPL_... symbols into strong aliases, which means we lose the ability to "hook" these functions when compiling for mingw-w64 target. But as mentioned in [microsoft#475], developers should stop doing this anyway. [microsoft#475]: microsoft#475
alvinhochun
added a commit
to alvinhochun/cppwinrt
that referenced
this pull request
Dec 17, 2022
Weak symbols on mingw-w64 target with GCC and the GNU linker is a bit broken for the intended use. When using the .weak + .set combo and the referenced symbol is undefined, LD does not produce an error but instead treat the referenced symbol like a weak symbol. This can happen if some of the link library flags is missing. The output executables will crash on run time, which can be very confusing. This change makes the WINRT_IMPL_... Windows API declarations on GNUC use asm labels instead. This means we lose the ability to "hook" these functions when compiling for mingw-w64 target. But as mentioned in [microsoft#475], developers should not be doing this anyway. [microsoft#475]: microsoft#475
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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.
Now that C++/WinRT supports activation extensibility, there's no reason to hook C++/WinRT externs any longer and this brittle practice can stop. To make this more explicit, the externs are renamed to reflect the C++/WinRT convention of using the WINRT_IMPL preamble to mark global functions/macros that are off limits.