How embarrassing - -O -W -Wall indeed found the problem with the program. Thank you very much! - Inga

In a message dated 7/1/2004 10:13:57 PM Eastern Daylight Time, Frank Heckenbach ih8mj@fjf.gnu.de writes:

What do you mean with register values? Assembler level registers? Of course, almost every operation changes them. Pascal variables? If they have a defined value, an operation without side-effects on them shouldn't change them, of course. (Otherwise it's in fact a compiler bug.)

*However*, if the variables are undefined, any operation can change their accidental values. That's what undefined means.

So I'd first look for this in your code. Did you compile with all warnings on, for a start? Please note that GPC doesn't find some such cases unless you compile with optimization. So `-O -W -Wall' would be a good start.

Frank