Re: What does -gnato do?

["Peter C. Chapin" <pchapin@sover.net>]

Martin Krischik <krischik@users.sourceforge.net> wrote in
news:1636357.gWrtX1Nq9K@linux1.krischik.com: 

> -gnato enables runtime checks but the warning results from a compile
> time check. The ability to make quite a lot of checks at compile time
> - rather then runtime - is a is one great advantage of the Ada Syntax
> and Sematic: 

You are right in that if I do the overflow with values that can only be 
known at run time, the -gnato makes a difference. Without the option, 
the results wrap around but with the option I get Constraint_Error.

So it seems that without -gnato the externally visible behavior of a 
program depends on the extent with which the compiler can analyze the 
code. If the compiler's analysis is sufficiently deep I might end up 
with a Constraint_Error that I wouldn't get if the analysis was not as 
deep. I'm not sure how I feel about that. It seems like a bad idea to me 
although I can't articulate exactly why I feel that way.

Peter