Re: GNAT-2005

[Martin Krischik <krischik@users.sourceforge.net>]

Adam Beneschan wrote:

> Stephen Leake wrote:
>> "rashmi" <rashmi.thoras@gmail.com> writes:
>>
>> > I have a problem with trying to understand GNAT's working for the
>> > following:
>> ><snip spec>
>>
>> > 3. I find that if I delete the first few lines that give specs for
>> > FUNC_ScBAVCK or FUNC_ScBAFCk, for which records are parameters, and
>> > then compile the package's body (.adb), GNAT does not report that
>> > functions are undefined. On the other hand, if I delete a specs line
>> > such as that for FUNC_BAVCPRd for which scalars are parameters, GNAT
>> > immediately reports "function FUNC_BAVCPRd undefined" when I compile
>> > the body.
>>
>> Without seeing the body, it's impossible to say.
>>
>> Most likely the bodies of the "scalar functions" are present in the
>> package body _before_ the places they are called.
> 
> That seems most likely to me, too.
> 
> Things have to be declared before they can be used (with few
> exceptions).  When you call one of these functions in the body, the
> compiler has to have seen it previously---either in the spec, or
> earlier in the body.  If you remove the declaration of a function from
> the spec, it's still OK to call it IF it is defined in the body before
> it's used---but not if it's defined in the body after it's used.  So
> that's probably why you're getting errors in some cases but not others.

Indeed, gnat with full warnings will actually create a warning if the
function only has a body but is not defined - either in the spec or earlier
in the body. This goes well with the gnat style checks which demand bodies
to be sorted.

Martin
-- 
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Ada programming at: http://ada.krischik.com