[libc-commits] [libc] [libc] Add __isoc99_fscanf alias. (PR #213125)

[Alexey Samsonov via libc-commits]

vonosmas wrote:

> I do not think that _just_ stubbing the function is a correct approach since isoc99_*scanf implies %a specifier which is used for string allocation to be present since it was made as a GNU extension and it was there way before POSIX's issue 7 %m modifier + it conflicts with %a specifier too.
> 
> https://man7.org/linux/man-pages/man3/sscanf.3.html#NOTES

We do not support (and I don't think ever will support) old-style GNU variant of using `%a` for allocation. llvm-libc just treats `%a` as a floating-point specifier.

*However*, I noticed that we have a `TODO` to add support for `%m` as well. @michaelrj-google  - do you remember if there were any blockers for it? (in either case, I don't think it should prevent this PR from merging).

https://github.com/llvm/llvm-project/pull/213125