Re: Please don't do this (code fragment)

[Olaf Weber <olaf@infovore.xs4all.nl>]

Manoj Srivastava writes:

> ... I see no references in the standard that require a particular
> behaviour on integer overflow, so I guess the behaviour is undefined
> by omission (though particular implementations may chose to have the
> behaviour well defined, if they wish).

Undefined by omission was also my conclusion.  As far as I know, the
standard is written like this to allow for ones-complement
implementations of signed integer, as well as for trapping on
overflow.

For the conversion of signed int to unsigned int and back, the
specification is such that one a twos-complement machine you can just
reinterpret the bit pattern.

Going back to the original code, the assumption that

        int i;
        for (i = 0; i > 0; ++i)
                ;

will terminate, and will terminate within a reasonable amount of time,
is not warranted.  The program _may_ crash when i overflows, and the
int type may be large enough that the program effectively hangs.

-- 
Olaf Weber

               (This space left blank for technical reasons.)