Re: Bounds checking

[Greg McGary <gkm at eng dot ascend dot com>]

Tristan Gingold <tgi@netgem.com> writes:

> > Checked and unchecked code may be mixed to the extent that checked and
> > unchecked code don't share aggregates (structs & arrays) containing
> > pointers whose size & layout change based on the size of pointers.
> 
> Just a question (as the author of Checker):  how will you manage stdio
> (for example) ?

You definitely put your finger on a problem area.  stdio is tough for
a couple reasons:
1) Layout of FILE is visible in getc & putc for some implemenations of stdio.
2) Printf & scanf accept varargs having pointer type.

The only ways I know to handle this is to
1) provide hand-written thunks (not the best way)
2) explicitly qualify the stdio interfaces as having unbounded
   pointers using the __unbounded cv-qualifier & attribute.
   (a better way, but requires hacking header files)
3) build stdio with bounded pointers (best if you have stdio source)

Greg