Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Mon, 27 Oct 2008 14:23:47 -0500

Hi Jens,

On Monday 27 October 2008 13:24:21 Jens Eden wrote:
> in Epics versions before R3.14.10-RC2, it was possible to build
> for a specific target arch only.
>
> e.g.
>
> > make vxWorks-68040
>
> would create dirs O.Common and O.vxWorks-68040 only in R3.14.9,
> In R3.14.10-RC2 the host arch will be built too and you end up with
> O.Common, O.vxWorks-68040 and O.linux-x86.
> This is a problem, because not all apps are supposed to compile with
> the host arch.

Janet has managed to fix this for the final release, but I would actually 
recommend that you fix the Makefile in those apps and not have to use that 
technique at all.

There are a number of variables that allow you to restrict the architectures 
that your code is compiled for, and if you get these right the problem 
vanishes.  For example, instead of
    LIBRARY = app
if you say
    LIBRARY_vxWorks = app
then that library will only be compiled for vxWorks targets.  You'll still get 
an O.linux-x86 directory, but it will be empty.

Here's an example Makefile from drvIpac/tyGSOctal, which creates a library 
libTyGSOctal.a on vxWorks and RTEMS, and uses a different C source file for 
each OS.  On other OSs it does nothing:

> # Makefile
> TOP = ..
> include $(TOP)/configure/CONFIG
>
> DBD += tyGSOctal.dbd
>
> LIBSRCS_vxWorks += tyGSOctal.c
> LIBSRCS_RTEMS += tyGSOctal_RTEMS.c
>
> LIBRARY_IOC_vxWorks = TyGSOctal
> LIBRARY_IOC_RTEMS = TyGSOctal
> TyGSOctal_LIBS += Ipac
>
> include $(TOP)/configure/RULES

The only thing the build system doesn't provide is the ability to restrict 
builds to a specific target architecture rather than an OS class.  It's not 
hard to do that yourself in the Makefile if you really need it though; I can 
explain how on request.

- Andrew
-- 
Talk is cheap. Show me the code. -- Linus Torvalds

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System