Use Python library from C++

I want to use the Python Libray from my C++ program.
The Python Libray is no GUI. How can I mix C++ and
Python?

One way is to run PY library as an independent process.
Another way is to start PY as a C++ thread.
The third way is to run Python engine as part of the C++.
Which way is better?

No intention to access all the Python's code but only
access APIs of a module.

Chang LI wrote:[color=blue]
> I want to use the Python Libray from my C++ program.
> The Python Libray is no GUI. How can I mix C++ and
> Python?
>
> One way is to run PY library as an independent process.
> Another way is to start PY as a C++ thread.
> The third way is to run Python engine as part of the C++.
> Which way is better?
>
> No intention to access all the Python's code but only
> access APIs of a module.[/color]

Try Elmer.

http://elmer.sf.net

--
Robert Kern
rkern@ucsd.edu

"In the fields of hell where the grass grows high
Are the graves of dreams allowed to die."
-- Richard Harter

Chang LI wrote:[color=blue]
> I want to use the Python Libray from my C++ program.
> The Python Libray is no GUI. How can I mix C++ and
> Python?
>
> One way is to run PY library as an independent process.
> Another way is to start PY as a C++ thread.
> The third way is to run Python engine as part of the C++.
> Which way is better?
>
> No intention to access all the Python's code but only
> access APIs of a module.[/color]

Try boost.python and SWIG?
(boost.sourceforge.net, swig.sourceforge.net)

Both provide a interface between C/C++ and python
if you want gui under python, you also can try wxpython or pygtk

zhao wrote:
[color=blue]
> Try boost.python and SWIG?
> (boost.sourceforge.net, swig.sourceforge.net)
>
> Both provide a interface between C/C++ and python
> if you want gui under python, you also can try wxpython or pygtk[/color]

I thought SWIG ported C/C++ libraries to Perl, Python, Ruby, Tcl, etc?
How would you use it to port Python into C/C++?

I think what you're looking for is instruction on how to embed Python in
your C/C++ application.

Chang LI a écrit :[color=blue]
> I want to use the Python Libray from my C++ program.
> The Python Libray is no GUI. How can I mix C++ and
> Python?
>
> One way is to run PY library as an independent process.
> Another way is to start PY as a C++ thread.
> The third way is to run Python engine as part of the C++.
> Which way is better?
>
> No intention to access all the Python's code but only
> access APIs of a module.[/color]

If you just want to access the Python API (or some APIs of modules) you
need to launch the interpreter (in the current thread will be ok) and
then you can access everything ... import modules, create objects, etc.

Pierre

Pierre Barbier de Reuille <pierre.barbier@cirad.fr> wrote in message news:<41a5b79a$0$17605$636a15ce@news.free.fr>...[color=blue]
>
> If you just want to access the Python API (or some APIs of modules) you
> need to launch the interpreter (in the current thread will be ok) and
> then you can access everything ... import modules, create objects, etc.
>[/color]

Yes. That is what I want (to launch Python Interpreter from C++ and use it)
Where is the document?
[color=blue]
> Pierre[/color]

"Chris S." <chrisks@NOSPAM.udel.edu> wrote in message news:<ukgpd.12554$Vy.6850@trndny06>...[color=blue]
> zhao wrote:
>[color=green]
> > Try boost.python and SWIG?
> > (boost.sourceforge.net, swig.sourceforge.net)
> >
> > Both provide a interface between C/C++ and python
> > if you want gui under python, you also can try wxpython or pygtk[/color]
>
> I thought SWIG ported C/C++ libraries to Perl, Python, Ruby, Tcl, etc?
> How would you use it to port Python into C/C++?
>[/color]

SWIG is for Python to use C++. I am searching for in reverse.
[color=blue]
> I think what you're looking for is instruction on how to embed Python in
> your C/C++ application.[/color]

On Fri, 2004-11-26 at 01:13, Chang LI wrote:
[color=blue]
> Yes. That is what I want (to launch Python Interpreter from C++ and use it)
> Where is the document?[/color]

http://docs.python.org/

Check out the C API reference and the embedding tutorial.

--
Craig Ringer

Chang LI wrote:[color=blue]
> "Chris S." <chrisks@NOSPAM.udel.edu> wrote in message news:<ukgpd.12554$Vy.6850@trndny06>...
>[color=green]
>>zhao wrote:
>>
>>[color=darkred]
>>>Try boost.python and SWIG?
>>>(boost.sourceforge.net, swig.sourceforge.net)
>>>
>>>Both provide a interface between C/C++ and python
>>>if you want gui under python, you also can try wxpython or pygtk[/color]
>>
>>I thought SWIG ported C/C++ libraries to Perl, Python, Ruby, Tcl, etc?
>>How would you use it to port Python into C/C++?
>>[/color]
>
>
> SWIG is for Python to use C++. I am searching for in reverse.[/color]

Elmer is the reverse of SWIG, and should be easier to use than using the
Python C API itself. Elmer will handle the conversion of types between
Python and C++ and will expose a nice API on the C++ side.

--
Robert Kern
rkern@ucsd.edu

"In the fields of hell where the grass grows high
Are the graves of dreams allowed to die."
-- Richard Harter

Robert Kern <rkern@ucsd.edu> wrote in message news:<co3qur$qdl$1@news1.ucsd.edu>...[color=blue]
>
> Try Elmer.
>
> http://elmer.sf.net[/color]

Looks like a perfect match between Python and C++.
Great thanks!

Chang

swig is a interface of C/C++ to python, but not in reverse.

In term of python document, there are extend and embed, and your need
is embed.

below is a short tutorial, maybe helpful:
http://tutorials.impereonsoft.com/python/extemb.html

if you work in windows, and you have install pywin32 package, it expose
a com interface of python interpreter,
so you also can use python's script or module in your application by
this interface.
if you use BCB, you can use a VCL component name "Python for Delphi".

Robert Kern <rkern@ucsd.edu> wrote in message news:<co3qur$qdl$1@news1.ucsd.edu>...[color=blue]
> Chang LI wrote:[color=green]
> > I want to use the Python Libray from my C++ program.
> > The Python Libray is no GUI. How can I mix C++ and
> > Python?[/color][/color]
.... (snip)[color=blue]
>
> Try Elmer.
> http://elmer.sf.net[/color]

There is also a library called PyCXX at http://cxx.sourceforge.net/.
It's main purpose is to provide a convenient C++ interface to the
Python C API. For example, it takes care of reference counting etc.
Although it's purpose is to write C++ extensions for Python, it should
be fairly easy to use it in reverse. It's a nice lib either way.