svn commit: r249355 - head/lib/libkvm

[Bruce Evans]

On Thu, 11 Apr 2013, Juli Mallett wrote:

> On Thu, Apr 11, 2013 at 11:00 AM, Gleb Smirnoff <glebius at freebsd.org> wrote:
>>   Bruce,
>>
>> On Thu, Apr 11, 2013 at 09:07:25PM +1000, Bruce Evans wrote:
>> B> Just routine avoidance of namespace pollution.  This is easy in such a
>> B> simple header.
>>
>> Sorry, with all respect, but I can't call including sys/types.h
>> a namespace pollution.
>>
>> Ok, even you force me to name it that way, still I would prefer
>> namespace pollution instead of handmade copy pasted typedefs.

The copying gives a good implementation.  Much easier to read (though
not write) than definitions in deeply nested includes.  We have too
many little include files to avoid duplication, but a few big nested
include files like machine/_types.h are hard to avoid.

> But Gleb, making such changes unilaterally is a bit of a leap.  The
> project has mostly accepted Bruce's wisdom about trying to minimize
> and reduce namespace pollution.  Now, this isn't a standard header so
> it's quite a bit less of a concern, but it's not no concern.  If you
> think that we should reverse our trend on including
> namespace-polluting headers in system headers, we should discuss that
> on arch@, and it shouldn't be something that's done without any
> discussion or consideration.
>
> Should we expect further changes of this nature (and of the proposed
> nature removing __size_t and __ssize_t use) if you make changes to
> other headers as part of your work?  Are you going to add
> <sys/types.h> to every header currently using <sys/_types.h> in a
> single go, or will you be doing that a little at a time when making
> functional changes?

That would be a large policy change, not to mention it would break most
C99 headers like <stdio.h>.  C99 headers can't include POSIX headers like
<sys/types.h> since the POSIX namespace rules don't apply to them.  Most
of them include sys/_types.h or machine/_types.h to get declarararions
like __size_t which they use to declare the limited set of typedefs
specified by C99.  C99 headers are relatively simple and mostly de-polluted.

Bruce