Undefined behaviour in C [was Re: The Cost of Dynamism]

[Paul Rubin]

BartC <bc at freeuk.com> writes:
>  But my suggestion was to have required a keyword in front of
> such expressions.

Should there be a keyword in front of a line containing "sqrt(x)" ?
What about "launch(missiles)" ?

The compiler can't tell which of those expressions has a side effect.
The first might be buggy code but the second is idiomatic.