Re: Posix message queues in linux?

[Nick Garnett <nickg at cygnus dot co dot uk>]

"Alan Cudmore" <Alan.P.Cudmore.1@gsfc.nasa.gov> writes:

> Hi,
> I sent this message to the mailing list before, but I figured that everyone
> was at Linuxworld in New York :)
> 
> I was reading the EL/IX draft spec under 3.13 Message Passing:
> 
> Does linux support POSIX message passing?
> If linux does not support it, is it going to be part of an EL/IX API that
> runs on Linux?

At present Linux does not support message passing. This is a minor
problem with some parts of the EL/IX specification: Linux is not yet
fully POSIX compliant. We expect this to change - there are already
patches available for some areas, and others are amenable to a
user-level implementation in glibc.

> 
> Is there a better way to do message passing in Linux & EL/IX. I am looking
> to have a capability similar to the RTOSs I am used to such as vxWorks and
> Nucleus.
> 

I do not believe that Linux provides any alternative message passing
mechanism - unless you count pipes! Since one of the goals of EL/IX is
to work with existing standards as much as possible, it would not be
appropriate for us to define a whole new message passing mechanism. I
do agree, however, that the message passing facilities in POSIX fall
somewhat short of what other RTOSs provide. 


-- 
Nick Garnett
Cygnus Solutions, a Red Hat Company
Cambridge, UK