Re: anyone ever crosscompile pvaPy?

["Johnson, Andrew N. via Tech-talk" <tech-talk at aps.anl.gov>]

Hi Peter,

On May 22, 2020, at 3:23 AM, Peter Milne via Tech-talk <tech-talk at aps.anl.gov> wrote:

We have a requirement to run pvaPy on a linux-arm system.
The ARM system is configured to provide a full EPICS7, Boost lib.

Following
https://github.com/epics-base/pvaPy/blob/master/README.md

Custom Build:

Seems to build fine for EPICS_HOST_ARCH=linux-x86_64

It's also putting in hooks for linux-arm:
ls ./src/pvaccess/O.linux-arm
Makefile

But that's it, no *.o, no pvaccess.so

### eg
pgm@staffa3 pvaPy]$ make
make -C ./configure install
....
make -C ./pvaccess install
make[2]: Entering directory '/home/pgm/PROJECTS/EPICS/pvaPy/src/pvaccess'
pgm TOP ../.. T_A
perl -CSD /usr/local/epics/base/bin/linux-x86_64/makeMakefile.pl O.linux-x86_64 ../../..
perl -CSD /usr/local/epics/base/bin/linux-x86_64/makeMakefile.pl O.linux-arm ../../..
mkdir -p O.Common
make -C O.linux-x86_64 -f ../Makefile TOP=../../.. \
   T_A=linux-x86_64 install
make[3]: Entering directory '/home/pgm/PROJECTS/EPICS/pvaPy/src/pvaccess/O.linux-x86_64'
pgm TOP ../../.. T_A linux-x86_64
/usr/bin/g++  -D_GNU_SOURCE -D_DEFAULT_SOURCE           -D_X86_64_  -DUNIX  -Dlinux     -O3   -Wall     -DPVA_API_VERSION=482 -DPVA_RPC_API_VERSION=482 -DHAVE_BOOST_NUM_PY=0 -DHAVE_BOOST_PYTHON_NUM_PY=1 -I/usr/include -I/usr/include/python3.7m  -mtune=generic      -m64 -fPIC -I. -I../O.Common -I. -I. -I.. -I../../../include/compiler/gcc -I../../../include/os/Linux -I../../../include -I/usr/local/epics/base/include/compiler/gcc -I/usr/local/epics/base/include/os/Linux -I/usr/local/epics/base/include        -MM -MF PyPvRecord.d  ../PyPvRecord.cpp

#### x86_64 builds all objects, but:

make[3]: Leaving directory '/home/pgm/PROJECTS/EPICS/pvaPy/src/pvaccess/O.linux-x86_64'
make -C O.linux-arm -f ../Makefile TOP=../../.. \
   T_A=linux-arm install
make[3]: Entering directory '/home/pgm/PROJECTS/EPICS/pvaPy/src/pvaccess/O.linux-arm'
pgm TOP ../../.. T_A linux-arm
make[3]: Nothing to be done for 'install'.
make[3]: Leaving directory '/home/pgm/PROJECTS/EPICS/pvaPy/src/pvaccess/O.linux-arm'
make[2]: Leaving directory '/home/pgm/PROJECTS/EPICS/pvaPy/src/pvaccess'
make[1]: Leaving directory '/home/pgm/PROJECTS/EPICS/pvaPy/src'


.... does nothing..


Is there any way to enable a cross-compile?
I don't see any PROD_HOST entries that could be changed to PROD, for example.

The important entry in src/pvaccess/Makefile is the line

LOADABLE_LIBRARY_HOST += pvaccess

Since pvaPy is a dynamic library that gets loaded by Python, there are no binaries to create so no use of the PROD or PROD_HOST variables in the Makefile. Change the above to LOADABLE_LIBRARY and it should start cross-compiling for your target.

Hopefully you and Sinisa can work out some way to adjust the build so cross-builds like this can be configured more easily, but I suspect it may always need some kind of manual configuration to enable it.

- Andrew

-- 

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