Re: master 37889523278: Add new `swap` macro and use it

[Po Lu]

Gregory Heytings <gregory@heytings.org> writes:

> FYI, Stefan's change did not break any build.  "typeof" is supported
> by all compilers with which Emacs can be built, either with the
> keyword "typeof" or with the keyword "__typeof__".  The only notable
> compiler that does not support "typeof" is MSVC, with which Emacs
> cannot be built.

Stefan's change (which I reverted) did not use __typeof__.

> "Every implementation in existence since C89 has an implementation of
> typeof. Some compilers (GCC, Clang, EDG, tcc, and many, many more)
> expose this with the implementation extension typeof. [...] This
> feature is the most "existing practice"-iest feature to be proposed to
> the C Standard, possibly in the entire history of the C standard. The
> feature was also mentioned in an "extension round up" paper that went
> over the state of C Extensions in 2007. typeof was also considered an
> important extension during the discussion of that paper, but nobody
> brought forth the paper previously to make it a reality."

Considering that EDG and GNU/Linux compilers are the only compilers you
have named as examples, this list is nowhere near sufficient to prove
that "typeof" does not break any build.  Which is a very presumptuous
statement whatever the length of your list, when a build breaking was in
fact the reason for this change...