Re: Which compiler is correct??

[bobduff@world.std.com (Robert A Duff)]

In article <514uuu$d8i@uuneo.neosoft.com>,
>I can see maybe 4 choices:  1)  GNAT is wrong, 2) ObjectAda is
>wrong, 3) the code is wrong, 4) I need to set some compile
>switches on one compiler or the other.

Looks like 1 and 3, to me.  Please send a bug report to ACT --
apparently GNAT doesn't understand that choice parameters are constant.

>On a PC with GNAT 304a touted as being compiled for Windows and
>GNAT 301 on a NeXT/M68040 I get no errors.
>
>With Academic ObjectAda v7.0.171 I get 3 occurrences of the same error
>along with line and column numbers.
>  
>      LRM:6.4.15(5) If the mode is IN OUT or OUT, the actual
>      shall be a name that denotes a variable.

It would have been easier if you had told me *which* line and column
numbers!  ;-)

>   exception
>      when error_in_square_function:
>        constraint_error => ada.exceptions.save_occurrence
>          (error_in_square_function,error_list(1));

You've got the parameters backwards.  Look up the spec of
Save_Occurrence.  Note that error_in_square_function is constant (by
RM-1.2(9)), so you can't pass it to an in-out param.

>        return 0;

Here, "raise;" would be more appropriate, at least in a real program.

- Bob