[ECOS] Re: net/bsd_tcp code conditional on (__NetBSD__ || __OpenBSD__)

[Grant Edwards <grant dot b dot edwards at gmail dot com>]

On 2012-03-07, Sergei Gavrikov <sergei.gavrikov@gmail.com> wrote:
> On Wed, 7 Mar 2012, Grant Edwards wrote:
>
>> I'm still working on clean up compiler warnings generated by gcc 4.6,
>> and all that's left is stuff under net/bsd_tcpip.  There are variables
>> that are set in code that's compiled unconditionally, but only
>> referenced in code that's conditional on 
>> 
>>   #if defined(__NetBSD__) || defined(__OpenBSD__)
>
> Would it possible "hide" those variables by the same condition?
>
> Oops, grep shows there are _too many_ such conditional checks. So, it
> is hard job

Exactly.  Some of those variables are set in several places, and
making all of them conditional would get messy.

>> Does eCos ever build that code with either __NetBSD__ or __OpenBSD__
>> defined?
>
> and no way to test fixes then.
>
>> If not, just removing the variables would seem to be cleaner than
>> marking them with the "unused" attribute.  [My guess is that the
>> compiler generates the same code either way, but I haven't verified
>> that.]
>
> I would avoid removing those variables even they are referred from the
> "died" blocks.

What I've done so far is that variables that are referenced by
conditionally compiled code are left in and declared with
CYGBLD_ATTRIB_UNUSED.   For examples, see

   http://bugs.ecos.sourceware.org/show_bug.cgi?id=1001525

>> However, removing the variables rather than marking them unused will
>> probably mean a lot more work when it comes time to incorporate
>> updates from upstream (which we all hope will happen someday when
>> "somebody else" has time to work on it).
>> 
>> So: remove or mark as "unused"?
>
> And may be leave all such places (=warnings) *as is* by that reason you
> pointed out?  What's about to enter a temporary suppression using the
> GCC diagnostic pragma  for net/bcd_tcp code?  (not tested, just an idea)
>
>   #pragma GCC diagnostic ignored "-Wunused-but-set-variable"

Personally, I prefer to do that on a per-variable basis so that the
warning is still enabled for other variables and will still catch a
"real" bug should one be introduced.

>   http://gcc.gnu.org/onlinedocs/gcc/Diagnostic-Pragmas.html
>
> Perhaps, that should be included with a check for GCC 4.X version.
>
> So: remove, mark as "unused", or leave as is?

-- 
Grant Edwards               grant.b.edwards        Yow! I want EARS!  I want
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