Re: renaming function result object inside loop

[Georg Bauhaus <rm.tsoh.plus-bug.bauhaus@maps.futureapps.de>]

Robert A Duff wrote:
> Georg Bauhaus <rm.tsoh.plus-bug.bauhaus@maps.futureapps.de> writes:
> 
>> Is the following a spurious warning?
>>
>>    528.          loop
>>    529.             declare
>>    530.                Line : String renames LIO.Get_Line; --!
>>                                                 |
>>         >>> warning: renaming function result object is suspicious
>>         >>> warning: function "Get_Line" will be called only once
>>         >>> warning: suggest using an initialized constant object instead
>>
>> (Get_Line in fact seems to be called each time around the loop.)
> [...]
> In the first case, Get_Line is called "once" (i.e. when the
> declaration of Line is elaborated), whereas in the second case,
> Get_Line is called every time you say "Line".
> 
> Since a constant:
> 
>     Line : constant String := LIO.Get_Line;
> 
> has the same semantics as the first renaming,
> it seems preferable (and if you're lucky, the
> compiler will generate the same code).

Thanks for the clarification.  I was in FUD whether
Ada 2005 had changed things in agreement with the warning.
Which I clearly have misunderstood.

A thought about both confusing issues with renaming result
objects then:  If 'Result makes it into the language,
is renaming a function result an opportunity to
allow 'Result?

   Line : String renames LIO.Get_Line'Result;


Anyway,
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41286