[PATCH] 6788196: Array bounds checks in io_util.c rely on undefined behaviour

[Dalibor Topic]

David Holmes - Sun Microsystems wrote:
> >> In C, the result of an overflowing add of two signed integers is
> >> undefined.
>
> Strewth! That's a surprise to me. I always thought that C defined 
> integer arithmetic to always wrap. 
Only for unsigned operands (from 6.2.5 - Types):

"A computation involving unsigned operands can never overflow,
because a result that cannot be represented by the resulting
unsigned integer type is reduced modulo the number that is one
greater than the largest value modulo reduced that can be
represented by the resulting type."

see p. 496 in the "The New C Standard: An Economic and Cultural 
Commentary" for more details then most people care. ;)

cheers,
dalibor topic

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