Re: Program error from assignment??

[Stephen Leake <Stephen.Leake@gsfc.nasa.gov>]

dennison@telepath.com writes:

> Program_Error can happen on this assignment when the accessability level of
> the source pointer's object is deeper than that of the target object's type.
> That's so I can't keep around a pointer to an object after it goes away. Fair
> enough.
> 
> So now this turns into an "accessability level" question. The object that is
> pointed to is declared in the declaration section of the main routine. It
> exists the entire program. I don't understand the exact rules on accessability
> levels, but in my book I should *never* fail an accessability check with this
> object. The access type is declared in a package spec.
> 
> T.E.D.

The compiler doesn't know that this routine is your main routine, so
it assumes it could be called from some other routine; then the
accessibility check makes sense. (uh oh; is this an advantage for C
"main"? :). 

You have two options:

1) Declare the object in a library level package (I usually call such
a package main_aux.ads or some such).

2) Use 'Unchecked_Access. This situation is pretty much what
Unchecked_Access is for; you are telling the compiler that you are
smarter than it is (well, at least you promise not to use the pointer
after the object goes out of scope :).

-- Stephe