on Fri, 24 Feb 2023 11:12:11 -0500 you (Tamir Duberstein
<tamird@google.com>) wrote:

> I agree, the caller's behavior is UB. I'll send them (freetype2) a
> patch.
> 
> That said, do we want to avoid internal UB here anyway?

I am not sure that I even understand what "internal UB" is supposed to mean.

> - As mentioned earlier, glibc avoids the UB (and the lock).
> - llvm-libc does the same starting with
> https://github.com/llvm/llvm-project/commit/53c251b
> - uclibc avoids the UB but still locks:
> https://github.com/gittup/uClibc/blob/9dbf00b/libc/stdio/fread.c#L25
> - FreeBSD avoids the UB but still locks:
> https://svnweb.freebsd.org/base/head/lib/libc/stdio/fread.c?view=markup#l76
> - Android (bionic) avoids the UB but still locks:
> https://cs.android.com/android/platform/superproject/+/master:bionic/libc/stdio/stdio.cpp;l=1099;drc=4aa8f499f21ebf84101de34d68682d5388667001
> 
> Does this persuade?

Me personally not much. The only thing that would help applications to
write portable code is to put an attribute on the pointer argument
such that bad calls get diagnosed if possible.

Jₑₙₛ

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