Re: An Ada Advice Inquiry

[Maciej Sobczak <see.my.homepage@gmail.com>]

On 8 Maj, 08:36, Martin Krischik <krisc...@users.sourceforge.net>
wrote:

> >> And still AFAIK there is still only
> >> one C++ compiler to support "export".
>
> > We've been through this already.
> > Short version: nobody uses "export" so nobody cares whether it's
> > supported or not. It looks that this subject is occupying the C++
> > enemies much more than the actual users of the language. Interesting,
> > isn't it?
>
> But isn't that a catch 22 - no one supports it because not one uses it
> because no one supports it. And there is no pressure to change because
> users don't know what they are missing.

Not really. There were high expectations at the beginning, because
people believed that "export" will allow them to hide (I mean -
literally, in terms of IP protection, not in terms of code structure)
implementation details of their template code. Without "export" the
library vendors have to ship all template code in open text, which
drives some of the managers crazy. After a couple of years, though, it
became clear that "export" does not guarantee this level of
protection, so today the motivation for having this feature is much
smaller.
That's why it's not true that people don't know what they are missing.

People learned to use templates without "export" and those who are
wary of code structure decouple the specification from implementation
with the crude use #include. It works just fine, thank you. It's not
perfect, but solving it doesn't provide any earth shaking benefits.
Note that in Ada (GNAT) the generic body needs to be available in
source form everywhere where it is instantiated.

Most importantly, implementing "export" is expensive (why do you think
only one vendor took the challenge) and there are bigger fishes to fry
- it's much better if vendors spend their cycles implementing some
other, really wanted functionality.

> I am not in favour of export because I am a C++ enemy.

You are not in favour or you are not an enemy? ;-)

Show me a short example of code that shows the benefits.

--
Maciej Sobczak
http://www.msobczak.com/