Is this something worth making a lint over?  It's pretty easy to make
regex-based lints, e.g.

yml-only based lint:
https://searchfox.org/mozilla-central/source/tools/lint/cpp-virtual-final.yml

yml+python for slightly more complicated regexing:
https://searchfox.org/mozilla-central/source/tools/lint/mingw-capitalization.yml
https://searchfox.org/mozilla-central/source/tools/lint/cpp/mingw-capitalization.py

-tom

On Mon, Aug 27, 2018 at 7:04 AM, Henri Sivonen <hsivo...@mozilla.com> wrote:

> Please don't use the functions from ctype.h and strings.h.
>
> See:
> https://daniel.haxx.se/blog/2018/01/30/isalnum-is-not-my-friend/
> https://daniel.haxx.se/blog/2008/10/15/strcasecmp-in-turkish/
> https://stackoverflow.com/questions/2898228/can-isdigit-
> legitimately-be-locale-dependent-in-c
>
> In addition to these being locale-sensitive, the functions from
> ctype.h are defined to take (signed) int with the value space of
> *unsigned* char or EOF and other argument values are Undefined
> Behavior. Therefore, on platforms where char is signed, passing a char
> sign-extends to int and invokes UB if the most-significant bit of the
> char was set! Bug filed 15 years ago!
> https://bugzilla.mozilla.org/show_bug.cgi?id=216952 (I'm not aware of
> implementations doing anything surprising with this UB but there
> exists precedent for *compiler* writers looking at the standard
> *library* UB language and taking calls into standard library functions
> as optimization-guiding assertions about the values of their
> arguments, so better not risk it.)
>
> For isfoo(), please use mozilla::IsAsciiFoo() from mozilla/TextUtils.h.
>
> For tolower() and toupper(), please use ToLowerCaseASCII() and
> ToUpperCaseASCII() from nsUnicharUtils.h
>
> For strcasecmp() and strncasecmp(), please use their nsCRT::-prefixed
> versions from nsCRT.h.
>
> (Ideally, we should scrub these from vendored C code, too, since being
> in third-party code doesn't really make the above problems go away.)
>
> --
> Henri Sivonen
> hsivo...@mozilla.com
> _______________________________________________
> dev-platform mailing list
> dev-platform@lists.mozilla.org
> https://lists.mozilla.org/listinfo/dev-platform
>
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