Multilib question

Joel Sherrill joel.sherrill at
Fri Feb 22 14:21:08 UTC 2002

Bill Butler wrote:
> Joel,
> First you have my deapest sinament about your family's loss.  I know
> this is a tough time.

Thanks. We are still waiting on the autopsy results so don't have any
specific arrangements. We know the funeral home and church but no
date/time yet. :(
> All,
> Could someone explain what multilib is for.  I get the feeling it is
> Grand.. I just don't understand enough about it to know why.
> But never wanting to be behind, today with 20020215 SS I installed with
> ../rtems-ss-20020215/configure --enable-multilib --prefix=/opt/rtems
> --target=m68k-rtems>
> make RTEMS_BSP="" preinstall
> make RTEMS_BSP=""
> so now what.?
> So I tried
> make RTEMS_BSP="<bsp>" preinstall  (working through a custom one )
> make RTEMS_BSP="<bsp>"
> make install?
> I have hunted around the past archive and online docs but have not found
> any reference to multilib that explains it.

The RTEMS multilib support is still not ready for prime time.  The
long term goal is to be able to treat RTEMS similar to how libc is.
The BSPs and some support libraries (libbsp, libchip, libcpu) would be 
separated out into a "BSP Kit".  As a user, you would be able to
get prebuilt RTEMS libraries and then locally build your BSP.  This
will limit the bulk that the average user has to deal with.

The big not so obvious advantage of this is that we should be able
to build add-on libraries (TCL, MicroWindows, zlib, etc) and provide
those as standard libraries.  The current build is focused on a BSP
and anything you build using an installed RTEMS is built for a

So long-term this is a nice win but there is still some work to be done.
Some of the ports are not 100% multilib clean and there has been no
work yet as to physically packaging the BSP Kit.  The --enable-multilib
switch lets us test building the parts of RTEMS that will be in the 
RTEMS library without the BSP Kit.  If anyone wants to contribute
to this effort, help is appreciated. 

> Thank you
> Bill
> >Hi,
> >There is a new RTEMS snapshot in the usual place:
> >
> >It is a significant step forward in the move to
> >a multilib'ed RTEMS and a separate BSP Kit.  There
> >have been many changes to the configurery to get
> >to this point.  The i386, powerpc, sh, and sparc
> >ports (I think) are the ones which still don't build
> >multilib style.  Help is appreciated to get this
> >all resolved.  What this means is that on those
> >ports, you can't build without having information
> >currently provided by libcpu or the BSP. To
> >build multilib, do this:
> >configure with --enable-multilib instead of --enable-rtemsbsp
> >make RTEMS_BSP="" preinstall
> >make RTEMS_BSP=""
> ..

Joel Sherrill, Ph.D.             Director of Research & Development
joel at                 On-Line Applications Research
Ask me about RTEMS: a free RTOS  Huntsville AL 35805
   Support Available             (256) 722-9985

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