Re: [makefile] adding a library to an EPICS application

[Martin Konrad <konrad@ikp.tu-darmstadt.de>]

Hi Pavel,
> What is the correct way to include a library to an EPICS app?
Including 3rd party libraries into an EPICS app is not as nice as it
could be...

Another thing I don't like about the EPICS build system: In many cases
application specific build rules are mixed with stuff that deals with
libraries that are installed somewhere on the system. But why at all
edit files to add library paths if they could be detected automatically
in most cases? Finding the location of a library like GSL or boost is
not an EPICS specific task. And there are modern build tools like CMake
that help you with this step.

So if your application depends on several non-EPICS libraries you might
want to consider building your app/IOC/lib with CMake. Here is what you
have to do:

1. Create a CMakeLists.txt file in each of your source directories. For
the correct contents consult the CMake documentation or the build
configuration of an EPICS application that already can be build with
CMake (like cagateway:
http://www.aps.anl.gov/epics/tech-talk/2011/msg01717.php).
2. Use FindXXX.cmake scripts to find all your libraries. CMake comes
with a lot of these scripts. There are ready-to-use scripts that help
you find the location of EPICS base, 3rd party libs, special build tools
etc.. See https://code.launchpad.net/~mdavidsaver/epics-base/cmake for
the scripts that find EPICS stuff.
3. To build your application run the following commands in the top level
directory:
mkdir build
cd build/
cmake ..
make

If you want to use a library from a non-standard location use

cmake -DMYLIB_INCLUDE_DIR=/home/pavel/include
-DMYLIB_LIBRARIES=/home/pavel/lib ..

Building with CMake has the advantage that you can do out-of-source
builds. You can also flexibly control the way and the location libraries
and headers are installed. CMake also handles the details of shared vs.
static libs.

Cheers

Martin

-- 
Dipl. Phys. Martin Konrad
Technische Universität Darmstadt
Institut für Kernphysik
Schlossgartenstr. 9
64289 Darmstadt
Tel.: +49-6151-16-5121
Fax: +49-6151-16-4321