Building C++ modules for python using GNU autotools, automake, whatever

[af300wsm at gmail.com]

On Thursday, February 26, 2015 at 9:35:12 AM UTC-7, Jason Swails wrote:
> On Thu, 2015-02-26 at 07:57 -0800, af300wsm wrote:
> > Hi,
> > 
> > I'm a complete neophyte to the whole use of GNU
> > autotools/automake/auto... .  (I'm not sure what it should be called
> > anymore.)  Regardless, I'm porting a library project, for which I'm a
> > team member, to using this toolset for building in Linux.  I'm to the
> > point now of writing the Makefile.am file for the actual library.
> > (There are several other static libraries compiled first that are
> > sucked into this shared object file.)  
> > 
> > I found some references here:
> > http://www.gnu.org/savannah-checkouts/gnu/automake/manual/html_node/Python.html, which seemed to be just what I was after.  However, I've got a big question about a file named "module.la" instead of "module.so" which is what we compile it to now.
> 
> I certainly hope module.la is not what it gets compiled to.  Open it up
> with a text editor :).  It's just basically a description of the library

Fascinating!  This is all new territory for me.  I'm used these tools for a number of years, of course, as I've run "./configure && make && make install" many times.  Now things are starting to make more sense.

> that libtool makes use of.  In the projects that I build, the .la files
> are all associated with a .a archive or a .so (/.dylib for Macs).
> Obviously, static archives won't work for Python (and, in particular, I
> believe you need to compile all of the objects as position independent
> code, so you need to make sure the appropriate PIC flag is given to the
> compiler... for g++ that would be -fPIC).

We are compiling all of our code with -fPIC.  I looked over the final build line and I see that a module.so was placed in .libs.  I looked in that directory and actually the module is named "module.so.0.0.0" and there is a symbolic link "module.so" which points to that.  This is cool stuff.


Thanks for the clarification on things.