Re: What's wrong with this code?

[dennison@telepath.com]

In article <m3zp43ywi8.fsf@mheaney.ni.net>,
  Matthew Heaney <matthew_heaney@acm.org> wrote:
> dennison@telepath.com writes:
>
> > I tried adding the following declarations:
> >     type Alarm_List is array (1..2) of Alarm_P;
> >
> >     type Alarm is tagged limited
> >     ...
> >             Al : Alarm_List := (others => Alarm'Access);
> >
> > And got this error (on the "Al" field) instead:
> > alarm_model.ads:52:43: non-local pointer cannot point to local object
>
> What message do you get if you use 'Unchecked_Access instead of 'Access?


Just the same old ""Access" attribute cann be applied to type". Good call.

I tried compiling the same code (the original code, not my modified
version) using my GreenHills (Intermetrics-based) compiler, and got:

d:\test\tmp\alarm_model.ads: Error: line 53 col 26 LRM:3.10.2(28), The
accessibility level of the prefix to 'ACCESS shall not be statically deeper
than that of the expected type of the allocator, Continuing

on the same line I got the above Gnat error. Changing the three "'Access"es to
"'Unchecked_Access" caused the GrennHills compile to succeed. But in Gnat the
same code gave me

alarm_model.ads:53:43: "Unchecked_Access" attribute cannot be applied to type
alarm_model.ads:54:41: "Unchecked_Access" attribute cannot be applied to type
alarm_model.ads:55:49: "Unchecked_Access" attribute cannot be applied to type


So it looks like one compiler (gnat) thinks the whole construct is illegal,
while the other (GreenHills) thinks the only problem is accessability levels.

--
T.E.D.

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