[C++-sig] Boost::Signals

John Reid johnbaronreid at netscape.net
Tue Jun 6 22:46:14 CEST 2006


I'm trying to call a python function from C++. I pass the function to 
C++ as a boost::python::object. I can call functions with no arguments, 
when I try to pass a C++ created object as an argument I get the 
following error:

Traceback (most recent call last):
   File "python/test_python.py", line 8, in ?
     d.connect_new_deal_slot_py_2( f )
TypeError: No to_python (by-value) converter found for C++ type: class 

Now the boost.python section (http://tinyurl.com/n3cpv) in the python 
wiki answers the following question:
"Is it is possible to convert pointers to existing classes to PyObjects* 
and then be able to pass an existing instance of an object directly to 
and from python?"

where the last paragraph says:

"If you really want to pass pointers around, it's certainly possible to 
tell the library to build a Python object around the pointer, but then 
you need to make sure the lifetime of the C++ object being referenced by 
the pointer extends past the lifetime of all Python references to the 
object or your program will crash."

This is what I would like to do but cannot find this elsewhere in the 
documentation. Can anyone let me know how to do this?

Thanks in advance,

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