mmap() w/o MAP_ANON

[Nicolas Williams]

On Thu, Apr 11, 2002 at 08:38:35AM -0500, Ben Lindstrom wrote:
> Yes and no..  MAP_PRIVATE must be MAP_SHARED  so all children can see
> the information written.  But otherwises yes.  Since it does not have a
> MAP_ANON we need to provide a FD to something.

MAP_PRIVATE mmap()s are in fact inherited by children procs.

MAP_SHARED is for mmap()ing some real file in such a way that changes
made via VM show up in mmap()ed segments of the same file *separately*
mmap()ed by other processes.

So MAP_PRIVATE of /dev/zero is the way to go. It's what ld.so does and
dynamically loaded libraries are, in fact, inherited across processes.


> - Ben


Cheers,

Nico
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