[C++-sig] Python, Boost.Python, and SCons

[Chad Austin]

Hey Graeme,

SCons is awesome!  (Bias note: I've been one of the developers since
shortly after the project went public.  But that's because I
immediately saw how much better a build tool using Python syntax is
than make.  Or pretty much anything, really.)  I use it to build every
project I start, especially the larger ones.  The focus on build
reliability and one global dependency tree is great.  You almost never
have to do an scons -c and scons in order to get a correct build.  And
when you do have to clean in order to verify it's correct, something
is buggy.  :)

Another advantage of SCons is Steven Knight, the guy who originally
created it.  He's an incredibly awesome manager and a nice guy all
around.  If you feel good about SCons, he does too.  If you don't feel
good, he and the rest of the community try to make SCons a little
nicer.

The SConstruct I attached is a total hackjob so I could get something
compiling as fast as possible.  A better one might look like:

def python_tool(env):
    pybase = 'python%s' % sys.version[0:3]
    env.Append(CPPPATH=[os.path.join(sys.prefix, 'include', pybase)],
               LIBPATH=[os.path.join(sys.prefix, 'lib', pybase, 'config')],
               LIBS=['lib%s' % pybase])
    if env['PLATFORM'] not in ['cygwin', 'win32']:
        env.Append(LIBS=['util'])

def boost_python_tool(env):
    env.Append(CPPDEFINES=['BOOST_PYTHON_STATIC_LIB',
                           'BOOST_PYTHON_STATIC_MODULE'],
               CPPPATH=['$boostIncludes'],  # boostIncludes is a PathOption
               LIBS=['boost_python-gcc'])

import os
env = Environment(ENV=os.environ, tools=['default', python_tool,
boost_python_tool])
env.SharedLibrary('hello', 'hello.cpp')

Then you could start to migrate in options (via the Options object)
and platform tests (via testing env['PLATFORM'] and such.

On this list, I keep hearing this vibe "you should use bjam to make
sure you get the voodoo build commands right, otherwise things will
fail in unpredictable ways."  I've never had a problem (win32, cygwin,
linux), though.  I just define BOOST_PYTHON_STATIC_LIB,
BOOST_PYTHON_STATIC_MODULE (for embedding), and
BOOST_PYTHON_NO_TEMPLATE_EXPORT (although this is kinda broken in
1.31).  Use SharedLibrary if you're building an extension module, etc.

Chad

On Fri, 2 Jul 2004 12:21:07 -0700, Graeme Lufkin
<graeme.lufkin at gmail.com> wrote:
> 
>     I'm interested to see you're using SCons to build your modules.
> Would you mind posting a short account of your experience using SCons,
> both in general and with Boost.Python?  I still wrestle with Makefile
> vs Boost.Build vs tearing-my-hair-out every once in while.  A more
> complicate SConstruct file would be great to look at too.  Thanks
> 
> On Fri, 2 Jul 2004 11:48:43 -0500, Chad Austin <caustin at gmail.com> wrote:
> > Chad at basilisk ~/tmp/bp
> > $ scons
> > scons: Reading SConscript files ...
> > scons: done reading SConscript files.
> > scons: Building targets ...
> > g++ -DBOOST_PYTHON_STATIC_LIB -DBOOST_PYTHON_NO_TEMPLATE_EXPORT -I/usr/local/inc
> > lude/boost-1_31 -I/usr/include/python2.3 -c -o hello.os hello.cpp
> > g++ -shared -o hello.dll hello.os -L/usr/lib/python2.3/config -L/usr/local/lib -
> > lboost_python-gcc -lpython2.3
> > scons: done building targets.
> >
> 
> --
>     -- Graeme
>     graeme.lufkin at gmail.com
> 
> 
> 
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-- 
Chad Austin
http://aegisknight.org/