Hi,

I apologize for the delayed reply.

I was hoping to avoid linking the commandManager into the .so file. I am trying to avoid that because then, I will have to do this for any other module that I create and uses the commandManager. I would prefer to declare it as extern or something similar if possible. If I link it into to .so, then I will have to link it to all the modules I intend to create, separately. Moreover, the commandManager is statically linked into my executable, so linking it in every single python module, feels like overkill. 

Furthermore, since my call to the commandManager looks like:

GetCommandManager()->submitCommand( new newDocumentCommand(makeActive) );

I will have to also link against the commands that will be sent to the commandManager as well. And if there are hundreds of commands, it's obvious that there is a lot of redundant stuff, since all these classes are also declared, defined and statically linked in the executable of my application.

So it all ends up to the question: Is it absolutely necessary? No other way?

On Tue, Sep 24, 2013 at 11:06 AM, Raghvendra Jain <raghavendra.jain@gmail.com> wrote:

Well, I have embedded an interpreter inside  C++ code, if your question is related to that, please write back. May be I can help you with that. 

cheers,

Raghav

On Tue, Sep 24, 2013 at 4:33 PM, Giuseppe Corbelli <giuseppe.corbelli@copanitalia.com> wrote:

On 21/09/2013 16:52, Kassiopi Kassiopi2 wrote:

Hi,

I want to call a c++ function from an embedded python shell, using boost
python. All the examples I've seen online describe how to expose a whole class

or some functions, but all cases refer to *standalone* parts of code.

My case is different though. The function I want to expose is not standalone,
and has a dependency:

------- start of documentModule.cpp --------
#include <commandManager.hpp>
#include <boost/python.hpp>

void newDocument( bool makeActive ) {
      // depends on commandManager here
     GetCommandMananager()->submitCommand( new newDocumentCmd( makeActive ) );
}

BOOST_PYTHON(documentModule) {
     using namespace boost::python;
     def( "newDocument", myCadLib::pythonCommands::newDocument,
arg("makeActive") );
}
------- end of documentModule.cpp --------

In reality the situation is more complicated and there are more dependencies
than the one mentioned above.
After generating a .so file with distutils, when I start my application and I
attempt to load the module (.so file) in the embedded python shell I get an
undefined symbols error complaining about the commandManager class.
Of course this is a reasonable request from python and I understand that.
However, I don't really care to generate a standalone python module per se. I
just want it to work in my application's embedded python shell. Additionally,
it wouldn't be meaningful to have the commandManager class exposed as well,
since this is part of my applications internal structure.

Seems to me you want both extending and embedding. Never embedded an interpreter in a C++ app, so I'm not of much use here.
The two jobs should be fairly independent. Producing the .so to extend the interpreter needs to link the commandManager library.
Your extension module needs to access the Command Manager, so make sure it has already been initialized before the module is loaded, else the GetCommandManager() may return NULL.

--
            Giuseppe Corbelli
WASP Software Engineer, Copan Italia S.p.A
Phone: +390303666318  Fax: +390302659932
E-mail: giuseppe.corbelli@copanitalia.com

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