Re: GNAT won't link on "warning"

[naasking@gmail.com (Sandro Magi)]

Martin Krischik <martin@krischik.com> wrote in message news:<3664370.5jO7nDmgDP@linux1.krischik.com>...
> Hello,
> 
> For demonstation purpose I wanted to write a program which will raise an
> exception on converting some data:
> 
> with Ada.Text_IO;
> 
> procedure Convert_Checked
> is
>    type Short_Short_Integer is range -(2**7) .. +(2**7-1);
>    type Byte                is mod   2**8;
>   
>    package T_IO renames Ada.Text_IO;
>    package M_IO is new  Ada.Text_IO.Modular_IO (Byte);
> 
>    A : constant Short_Short_Integer := -1;
>    B : constant Byte                := Byte (A);
> begin
>    T_IO.Put ("B = ");
>    M_IO.Put (
>       Item  => B,
>       Width => 5,
>       Base  => 10);
> end Convert_Checked;
> 
> When I compile the demo I get:
> 
> convert_checked.adb:12:40: value not in range of type "Byte" defined at line
> 6
> convert_checked.adb:12:40: static expression raises "Constraint_Error"
> 
> It is my intention to use a value which is not in range of type "Byte" and
> "Constraint_Error" is precicly what I want to demonstate.

GNAT has determined at compile-time that the value is out of range for
the type you specified.

> However, GNAT won't link the program. Actually GNAT won't even create an *.o
> file. Is this right? Is there an option to force creation?

pragma Suppress(Range_Check)

will suppress the run-time checks, but I'm not sure if it wil suppress
compile-time checks. The best way to test run-time exception cases is
to read some data in from some external source (like the command-line
or a file). There are examples to do this on http://www.adapower.com