[C++-sig] call_f(Derived) did not match C++ signature

[aashish at iastate.edu]

I think what you are doing wrong is instead of passing the object of
Derived you are passing the class itself
do this:

from test_foo import *

class Derived(Base):
    def f(self):
        return 42

derived = Derived()
print derived.f()
print call_f(derived)
------------------------------------

and in C++

#include <boost/python.hpp>

using namespace boost::python;

struct Base{
		virtual int f() = 0;
};

int call_f(Base& b) {return b.f();}

struct BaseWrap : Base{
	BaseWrap(PyObject* self_) : self(self_){}
	int f() { return call_method<int>(self,"f") ;}
	PyObject* self;
};

BOOST_PYTHON_MODULE(test_foo) {
 class_<Base, BaseWrap, boost::noncopyable>("Base") ;
 def("call_f", call_f);
}
---------------------------------

if you look carefull the call_f takes the ref to Base ...

Hope this helps,
~aashish



>/doc/class_virtual_functions.html
>
> But I have a problem ...
> I compiled this example as module foo and ran test_foo.py
> attached to this mail.
> Then I had following errors:
>
> ====== BEGIN OUTPUT ======
> *****************************************************************
> Failure in example: foo.call_f(a)
> from line #9 of test_foo
> Exception raised:
> Traceback (most recent call last):
>   File "/home/shin/.local/lib/python2.3/doctest.py", line
> 442, in _run_examples_inner
>     compileflags, 1) in globs
>   File "<string>", line 1, in ?
> ArgumentError: Python argument types in
>     foo.call_f(Derived)
> did not match C++ signature:
>     call_f(Base {lvalue})
> *****************************************************************
> 1 items had failures:
>    1 of   4 in test_foo
> ***Test Failed*** 1 failures.
>
> EXIT STATUS: 1
> ====== END OUTPUT ======
>
> What's wrong?
> Thanks.
>
>
>
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-----------------------------------------------
Aashish Chaudhary       | Email:
Research Assistant      | ashish_cy at yahoo.com
Iowa State University   | aashish at iastate.edu
Ames, Iowa - USA        | Ph: (515) 441-1178
-----------------------------------------------