Re: With Exceptions Disabled On Windows, How Can I Determine Where A Software Interrupt Occurs

[sjw <simon.j.wright@mac.com>]

On Oct 20, 7:23 pm, Pascal Obry <pas...@obry.net> wrote:
> Le 20/10/2009 20:01, ChristopherL a écrit :
>
> > I'm looking for a compilable/working example on how to do this. For
> > example code to determine where a divide by zero occurs etc.
>
> With GNAT?
>
> Nothing, you should get something like this when running your application:
>
>     raised CONSTRAINT_ERROR : buf.adb:12 divide by zero
>
> > If I can't get the code what can you tell me?
>
> To have full backtrace and also check for overflow you should compile
> your application with -gnato and pass -E on the binder:
>
>     $ gnatmake prog -cargs -gnato -bargs -E

GNAT doesn't raise numeric overflow exceptions for plain floats,
though it will raise CE if you declare the right subtypes: this

with Ada.Text_IO; use Ada.Text_IO;
procedure Divide_By_Zero is
   subtype Flt is Float;
   function Div (Denominator, Numerator : Flt) return Flt is
   begin
      return Denominator / Numerator;
   end Div;
begin
   Put_Line (Float'Image (Div (1.0, 0.0)));
   Put_Line (Float'Image (Div (-1.0, 0.0)));
   Put_Line (Float'Image (Div (0.0, 0.0)));
end Divide_By_Zero;

outputs

$ ./divide_by_zero
 +Inf*******
-Inf*******
NaN********

but if you replace the declaration of Flt by

   subtype Flt is Float range Float'Range;

you get

raised CONSTRAINT_ERROR : divide_by_zero.adb:6 range check failed