Re: GCC 4.9.1 suggests -std=c99

[Paul Eggert <eggert@cs.ucla.edu>]

Eli Zaretskii wrote:
> we should have discussed whether to use these C99 features
> before actually starting using them.

We discussed them in Bug#17487.  As I mentioned, Emacs developers 
routinely made changes that used these features, I was occasionally 
auditing the code and removing their use for no practical reason (only 
because of standards-conformance issues), and I got tired of this 
pointless task.

My guess is that when Michael Albinus introduced the 'for (int i = 1; 
...' loop in trunk bzr 117771, he wasn't consciously thinking "Oh boy! I 
get to use C99 now! I will now change Emacs's style!"  Most likely he 
was just using a common and natural idiom that worked for him, and 
didn't notice that it wouldn't port to C89 and was therefore contrary to 
Emacs's old style rules.

> Emacs definitely has certain
> coding style, which doesn't include these.

The part of Emacs's style that disallowed these C99 features was there 
primarily because of C89's restrictions.  It's often not the best style 
and we should not insist on it.

I agree with Dmitry that we should not insist on a declaration as the 
first clause of every for loop, but there doesn't seem to be a good 
reason to prohibit a declaration there, whereas there is a good reason 
(more-accurate scoping) to allow it.