Re: [HACKERS] mmap and MAP_ANON

ocie@paracel.com

From: ocie@paracel.com
To: maillist@candle.pha.pa.us (Bruce Momjian)
Cc: ocie@paracel.com, hackers@postgreSQL.org
Date: 1998-05-12T20:24:21Z
Lists: pgsql-hackers
Bruce Momjian wrote:
> 
> > 
> > Bruce Momjian wrote:
> > > 
> > > Would people tell me what platforms do NOT support the MAP_ANON flag to
> > > the mmap() system call?  You should find it in the mmap() manual page.
> > 
> > Doesn't seem to appear in Linux (2.0.30 kernel).  As another poster
> > commented, /dev/zero can be mapped for anonymous memory.
> > 
> 
> OK, who doesn't have /dev/zero?

I have been playing around with mmap on Linux.  I have been unable to
mmap /dev/zero or to use MAP_ANON in conjunction with MAP_SHARED.
There is no problem sharing memory when a real file is used.
Solaris-sparc seems to have no trouble sharing memory mapped from
/dev/zero.  Very strange.

Ocie