Re: How to do null comparision with pointers in ADA83?

[Adam Beneschan <adambeneschan@aol.com>]

On Friday, October 25, 2013 11:12:00 AM UTC-7, seshuch...@gmail.com wrote:
> Hello,
> 
> In ADA83, i could not able to do null comparision of my pointer value.
> here, my pointer is of array type.
> 
> Is there any solution for this.
> 
> Thanking you in advance.

We really need to see the code.  But here's my first guess: When you declare an access type in a package, the "=" operator that lets you compare values of the access type is also declared in the same package.  In another package, you can't use the "=" operator unless the names in the first package are visible.  So this won't work if you're not inside package P:

    Acc : P.Access_Type;
begin
    if Acc = null then ...

You'd need to either put "use P;" somewhere, or do something like this:

    if P."=" (Acc, null) then ...

or you could use a rename to make "=" visible if you don't want to use "use P":

    function "=" (Left, Right : P.Access_Type) return boolean
        renames P."=";

and now you can use = as an operator everywhere that this renaming declaration is visible.

If this isn't the problem, then I think we need to see some code.

                                    -- Adam