Re: Limited_Controlled types and generic formal parameters

Re: Limited_Controlled types and generic formal parameters

[Robert A Duff]

In article <goliver.1.000B3230@magnus.acs.ohio-state.edu>,
Guy L. Oliver <goliver@magnus.acs.ohio-state.edu> wrote:
>The problem seems to be that the generic package can not tell that item  
>(one of the generic formal parameters) is a derived type of limited 
>controlled.  When I wrote a test program to see what was being initialized, I 
>saw that the item in the box was not being initialized.  After consulting the 
>AARM, I am nearly certain that it should have.  

Sounds like a compiler bug.  Every object of a controlled type gets
Initialize called for it.  That includes components (components are
objects), and it even includes components whose type is a generic formal
type that isn't visibly controlled.

One exception: when you write an aggregate, this creates a temporary
object, and Initialize is not called for that temp -- when you write an
aggregate, you're asking for certain component values, and you don't
want them modified.  Usually, a controlled type will be a private type,
or a private extension, so aggregates are only allowed within the
package itself.

- Bob

Re: Limited_Controlled types and generic formal parameters

[Cyrille Comar]

bobduff@world.std.com (Robert A Duff) writes:
: 
: Sounds like a compiler bug.  Every object of a controlled type gets
: Initialize called for it.  That includes components (components are
: objects), and it even includes components whose type is a generic formal
: type that isn't visibly controlled.
: 

It is more in the category of unimplemented (and clearly documented)
features.... GNAT 2.00 was doing exactly 'nothing' with controlled
components, let alone the wierd case of the original message...
Just another reminder that GNAT is not (yet?) a validated Ada9x
compiler so it is prudent to check the 'features' file before any
experiment (or at least before drawing any conclusion from them)

-- 
------------------------------------------------------------------------
Cyrille Comar,                                  E-mail: comar@cs.nyu.edu
Gnat Project                                    US phone: (212) 998-3489