Re: posix 4 extensions

Stephen C. Tweedie (
Wed, 31 Jul 1996 08:27:43 +0100


On Tue, 30 Jul 96 23:16 CDT, (Johnie Stafford) said:

sct> The posix.4 real time scheduling classes are supported in 2.0. Most
sct> of the other posix.4 stuff requires real time signals, and doing that
sct> would require too much change in the kernel to make so close to 2.0.
sct> Hopefully you'll see it in 2.1. There was a BOF session at the Berlin
sct> LinuxKongress where real time linux was discussed, btw.

> What about the posix.4 shared memory objects? Any chance we might ever
> see them? The ability to map shared memory segments to the same
> logical address in several different processes would make the use of
> pointers in shared memory possible.

Posix shared memory is really no different from the sysV-style shared
memory which linux already supports. The main differences are just
that posix uses file descriptors to map the memory instead of doing it
via shmat(), and that posix uses a different naming space to identify
shared memory segments.


Stephen Tweedie <>
Department of Computer Science, Edinburgh University, Scotland.