Re: Matching regex case-sensitively in C strings?

[Eli Zaretskii]

> From: Mattias Engdegård <mattiase@acm.org>
> Date: Tue, 8 Nov 2022 11:18:10 +0100
> Cc: Eli Zaretskii <eliz@gnu.org>, emacs-devel <emacs-devel@gnu.org>
> 
> >  // What does freezing a pattern do?
> >  freeze_pattern (cache_entry);
> 
> It locks the compiled pattern record to make the regexp engine reentrant (but 
> here it also seems to be used for GC purposes; not sure about that).

See shrink_regexp_cache, which is called by GC.  You don't want this
to happen to you when you are in the middle of a regexp search.