Re: Libraries written in Ada

["Alex R. Mosteo" <devnull@mailinator.com>]

Thomas Lotze wrote:
> On Tue, 23 Nov 2004 10:48:45 +0100, Martin Krischik wrote:
> 
> 
>>can be preelaborated by the compiler and then no runtime elaboration is
>>needed.
> 
> 
> How can I find out whether the code produced by the compiler (not a
> specific one, but any compiler that conforms to the spec) needs runtime
> elaboration? Are there simple rules such as "this code pattern may or does
> require runtime elaboration while that pattern can be safely assumed to
> work without"? I'd have to dig further through the references, but I
> haven't found a clear statement so far.

Look for the pragma No_Runtime if you're using Gnat.

And look in the Ada Reference Manual for the pragmas Pure, Preelaborate 
& Elaborate_Body for elaboration concerns. I read these from time to 
time and always manage to forget the details ;)

In particular, I'm not sure about the situation when your package can't 
have "preelaborate" and you don't specify an "elaborate_body". It's not 
the same (at least Gnat doesn't behave the same).

And then there's that "elaborate" and "elaborate_all" which I suspect 
that apply in the previous case, but I never like to use. I don't like 
the package that uses another to have to worry about such pragmas, I 
prefer to have everything self-managed when possible. But maybe I'm 
confusing something.

Finally you have that Gnat warning switch (that I don't remember now) 
which will warn you about elaboration order problems. Activating it late 
in a project will make you cry when you see the lots of "elaborate_all 
needed" it reports and you don't understand why :P

Hint to adapower and adaworld :D : Set Up an explanation for the 
elaboration misteries of Ada in non-ARM speak.