Re: [Boost-users] Exposing C++ Instances to Python

Are you finding "Boost.Python.register_ptr_to_python" ? Please look this document http://www.boost.org/doc/libs/1_41_0/libs/python/doc/v2/register_ptr_to_pyth... Is this sample same as you require ? Thanks, Xiongjia Le ( http://notes.xj-labs.net/ ) On Tue, May 25, 2010 at 11:34 PM, Leonhard Weber wrote:

Made a mistake... srry for my lacking knowledge/experience in C++. Trying to improve :D.

For test purposes I changed the Python Script so it inits an instance, and then tries to fetch the instance through the PyCallback: ##### from EngineCallback import *

a = EngineCallback() b = PyCallback(a)

...

...

...

a b

##### On the C++ side I had to change this, its now passing the argument by value (which I dont want) shared_ptr<EngineCallback> PyCallback( EngineCallback* test ) { return shared_ptr<EngineCallback>(test); }

If I passed it per reference EngineCallback* &test (hope Im getting the jargon right and not mixing up definitions) it would say:

did not match C++ signature: PyCallback(EngineCallback* {lvalue})

by changing it to pass by value it works, though isnt it making a copy of the instance? how do I get just a reference to the instance passed to Python?

On 25 May 2010 16:56, Steven Watanabe wrote:

...

AMDG

Leonhard Weber wrote:

...

EngineCallback* test = new EngineCallback;

// Entrypoint for Python to come ant fetch the Application Callback shared_ptr<EngineCallback> PyCallback( EngineCallback* &test ); <snip>

# test.py from EngineCallback import PyCallback from EngineCallback import EngineCallback

test = PyCallback()

PyCallback takes one argument. Hence the exception below. Did you intend to use the global "test" instead of taking test as an argument in PyCallback?

Traceback (most recent call last):

...

File "test.py", line 5, in <module> test = PyCallback() Boost.Python.ArgumentError: Python argument types in EngineCallback.PyCallback() did not match C++ signature: PyCallback(EngineCallback* {lvalue})

In Christ, Steven Watanabe

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