Experimental Physics and
Industrial Control System

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