brk's zero-fill behavior on VAXen

Arthur David Olson ado at elsie.UUCP
Mon Nov 3 12:09:11 AEST 1986


In section 2 of the UNIX Programmer's Manual, the description of the "brk" and
"sbrk" calls note only that they change the system's notion of the lowest
location not used by the program.  If the result of the call is to expand the
address space of the process, there's no promise about the contents of the
newly-available address space.  Yet on our VAX (and on yours, too, if you
have one) the newly-available space is always zero filled.

Can system performance be improved by avoiding zero filling of the new
memory?
--
UNIX is a registered trademark of AT&T.
--
	UUCP: ..decvax!seismo!elsie!ado   ARPA: elsie!ado at seismo.ARPA
	DEC, VAX, Elsie & Ado are Digital, Borden & Ampex trademarks.



More information about the Comp.unix.wizards mailing list