Re: Exceptions in GNAT

[David Rasmussen <pinkfloydhomer@yahoo.com>]

David Rasmussen wrote:
> I am learning Ada, and in one exercise I am told to find out how large 
> and integer I can use on my system, before it overflows. The exercise 
> just tells me to add two larger and larger numbers and see when an 
> exception occurs. I have just compiled my program with gnatmake with no 
> options, and I am using gcc 3.1 . When the numbers get large enough, the 
> result is just a negative number because of wrap-around. Shouldn't I get 
> an exception, unless I turn it off? How do I compile for with most 
> checks for debug builds, and how do I compile with everything turned off 
> for performance intensive release builds?
> 
> /David
> 

D'oh.... This is weird:

Enter two integers: 2100000000 0
The sum is 2100000000
david@amadeus-T23:~/src/Ada/Ex21$ ./sum
Enter two integers: 2200000000 0


raised ADA.IO_EXCEPTIONS.DATA_ERROR : a-tiinio.adb:91 instantiated at 
a-inteio.ads:20
david@amadeus-T23:~/src/Ada/Ex21$ ./sum
Enter two integers: 2147483648 0


raised ADA.IO_EXCEPTIONS.DATA_ERROR : a-tiinio.adb:91 instantiated at 
a-inteio.ads:20
david@amadeus-T23:~/src/Ada/Ex21$ ./sum
Enter two integers: 2147483647 0
The sum is 2147483647
david@amadeus-T23:~/src/Ada/Ex21$ ./sum
Enter two integers: 2147483647 1
The sum is-2147483648
david@amadeus-T23:~/src/Ada/Ex21$ ./sum
Enter two integers: 2147483647 2
The sum is-2147483647
david@amadeus-T23:~/src/Ada/Ex21$

Sometimes there's an exception, and sometimes there isn't... What's 
happening??

/David