On Thu, Jun 28, 2012 at 9:47 AM, Jon Nelson <jnelson+pg...@jamponi.net> wrote: > Why not just mmap /dev/zero (MAP_SHARED but not MAP_ANONYMOUS)? I > seem to think that's what I did when I needed this functionality oh so > many moons ago.
From the reading I've done on this topic, that seems to be a trick invented on Solaris that is considered grotty and awful by everyone else. The thing is that you want the mapping to be shared with the processes that inherit the mapping from you. You do *NOT* want the mapping to be shared with EVERYONE who has mapped that file for any reason, which is the usual meaning of MAP_SHARED on a file. Maybe this happens to work correctly on some or all platforms, but I would want to have some convincing evidence that it's more widely supported (with the correct semantics) than MAP_ANON before relying on it. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
