[TALK] Proving fundamental Unix guarantees

Gary Schmidt gary.schmidt at oz.quest.com
Mon Jun 30 14:33:24 EST 2003

> This may be a bit too work-related for this list, but anyway:
> In response to a query, one of our Unix vendors has stated
> "OS-name-deleted-to-protect-the-guilty does not guarantee that all
> memory given to a program is necessarily initialised" and "there are
> regions known as BSS which hold data (i.e. program variables) which
> ARE NOT INITIALISED.  What this means is that these variables will
> hold whatever was in that memory location before it was allocated to
> them. ...  This is designed behaviour".
> This is, of course, nonsense - Unix does guarantee that all memory
No, it is not nonsense.

There is no guarantee that uninitialised memory will be set to anything.

On some UNICES memory _may_ be initialised, but don't rely on it.

I don't have any POSIX or SVID citations for it, just twenty-odd years, and the current half-a-dozen different UNIX boxen in front of me.

		Gary	B-)

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