GNU bug report logs - #21707
include-file cleanup for src directory

Previous Next

Full log

Message #38 received at 21707 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: 21707 <at> debbugs.gnu.org
Subject: Re: bug#21707: include-file cleanup for src directory
Date: Tue, 20 Oct 2015 13:52:42 -0700

On 10/20/2015 12:15 PM, Eli Zaretskii wrote:
> Even standard C headers sometimes require order, for example, 
> sys/types.h should be included before sys/stat.h.

Oh my goodness your memory goes a long way back!  But the C Standard 
never required a particular header order (it never standardized 
sys/types.h or sys/stat.h). POSIX did originally require that one must 
include both <sys/types.h> and <sys/stat.h> before using functions like 
'stat', but that requirement was removed a while ago; e.g., nowadays 
only <sys/stat.h> must be included before using 'stat'.  And it's not 
hard to see why the old POSIX requirement was removed: a .h file should 
describe an API standalone, to avoid unnecessarily constraining the 
API's users.

> I thought we could perhaps come up with a method that would allow 
> anyone easily see which headers are needed on every supported platform

I started something along those lines, but it's harder than it looks. 
The current patch came from my woefully-inadequate approximation to the 
tools I wanted.

> I think the real problem is to keep this state once we get there.

Yes. Part of the job would be to write better checking tools. And part, 
I expect, would be to simplify Emacs's complicated uses of headers. For 
example, although we sometimes have headers A and B that use each 
others' symbols, it wouldn't be cool to have both A #include B and B 
#include A. Some of this simplification will likely be needed anyway, as 
we change more macros to inline functions.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.