I'm trying to compile the example from the Boost Python docs without
success.
hello.cpp:
#include <boost/python.hpp>
char const * const greet() {
return "hello, world";
}
BOOST_PYTHON_MODULE(hello_ext) {
using namespace boost::python;
def("greet", greet);
}
I have Boost 1.48, Python 2.7, and gcc 4.7.0.
When I do this:
g++ -fPIC -I/usr/include/python2.7 -c -o hello.o hello.cpp
I get the following errors:
In file included from
/usr/include/boost/preprocessor/iteration/detail/iter/forward1.hpp:47:0,
from /usr/include/boost/python/detail/invoke.hpp:63,
from /usr/include/boost/python/detail/caller.hpp:16,
from /usr/include/boost/python/object/function_handle.hpp:8,
from /usr/include/boost/python/converter/arg_to_python.hpp:19,
from /usr/include/boost/python/call.hpp:15,
from /usr/include/boost/python/object_core.hpp:14,
from /usr/include/boost/python/args.hpp:25,
from /usr/include/boost/python.hpp:11,
from hello.cpp:1:
/usr/include/boost/python/detail/invoke.hpp: In instantiation of âPyObject*
boost::python::detail::invoke(boost::python::detail::invoke_tag_<false, false>,
const RC&, F&) [with RC =
boost::python::detail::specify_a_return_value_policy_to_wrap_functions_returning<const
char* const>; F = const char* const (*)(); PyObject = _object]â:
/usr/include/boost/python/detail/caller.hpp:223:13: required from
âPyObject* boost::python::detail::caller_arity<0u>::impl<F, Policies,
Sig>::operator()(PyObject*, PyObject*) [with F = const char* const (*)();
Policies = boost::python::default_call_policies; Sig =
boost::mpl::vector1<const char* const>; PyObject = _object]â
/usr/include/boost/python/object/py_function.hpp:38:33: required from
âPyObject*
boost::python::objects::caller_py_function_impl<Caller>::operator()(PyObject*,
PyObject*) [with Caller = boost::python::detail::caller<const char* const
(*)(), boost::python::default_call_policies, boost::mpl::vector1<const char*
const> >; PyObject = _object]â
hello.cpp:10:1: required from here
/usr/include/boost/python/detail/invoke.hpp:75:19: error: no match for call to
â(const
boost::python::detail::specify_a_return_value_policy_to_wrap_functions_returning<const
char* const>) (const char*)â
In file included from /usr/include/boost/python/object/function_handle.hpp:8:0,
from /usr/include/boost/python/converter/arg_to_python.hpp:19,
from /usr/include/boost/python/call.hpp:15,
from /usr/include/boost/python/object_core.hpp:14,
from /usr/include/boost/python/args.hpp:25,
from /usr/include/boost/python.hpp:11,
from hello.cpp:1:
/usr/include/boost/python/detail/caller.hpp: In instantiation of âstatic
const PyTypeObject*
boost::python::detail::converter_target_type<ResultConverter>::get_pytype()
[with ResultConverter =
boost::python::detail::specify_a_return_value_policy_to_wrap_functions_returning<const
char* const>; PyTypeObject = _typeobject]â:
/usr/include/boost/python/detail/caller.hpp:242:13: required from âstatic
boost::python::detail::py_func_sig_info
boost::python::detail::caller_arity<0u>::impl<F, Policies, Sig>::signature()
[with F = const char* const (*)(); Policies =
boost::python::default_call_policies; Sig = boost::mpl::vector1<const char*
const>]â
/usr/include/boost/python/object/py_function.hpp:48:35: required from
âboost::python::detail::py_func_sig_info
boost::python::objects::caller_py_function_impl<Caller>::signature() const
[with Caller = boost::python::detail::caller<const char* const (*)(),
boost::python::default_call_policies, boost::mpl::vector1<const char* const>
>]â
hello.cpp:10:1: required from here
/usr/include/boost/python/detail/caller.hpp:102:109: error: âstruct
boost::python::detail::specify_a_return_value_policy_to_wrap_functions_returning<const
char* const>â has no member named âget_pytypeâ
In file included from
/usr/include/boost/python/converter/pytype_function.hpp:10:0,
from /usr/include/boost/python/to_python_indirect.hpp:16,
from /usr/include/boost/python/converter/arg_to_python.hpp:10,
from /usr/include/boost/python/call.hpp:15,
from /usr/include/boost/python/object_core.hpp:14,
from /usr/include/boost/python/args.hpp:25,
from /usr/include/boost/python.hpp:11,
from hello.cpp:1:
/usr/include/boost/python/detail/unwind_type.hpp: In instantiation of
âtypename Generator::result_type
boost::python::detail::unwind_type(boost::type<U>*, Generator*) [with Generator
= boost::python::converter::detail::unwind_type_id_helper; U = const char*
const; typename Generator::result_type = boost::python::type_info]â:
/usr/include/boost/python/converter/pytype_function.hpp:45:74: required from
âboost::python::type_info
boost::python::converter::detail::unwind_type_id_(boost::type<T>*,
mpl_::false_*) [with T = const char* const; mpl_::false_ =
mpl_::bool_<false>]â
/usr/include/boost/python/converter/pytype_function.hpp:68:13: required from
âstatic const PyTypeObject*
boost::python::converter::expected_pytype_for_arg<T>::get_pytype() [with T =
const char* const; PyTypeObject = _typeobject]â
/usr/include/boost/python/detail/signature.hpp:98:13: required from âstatic
const boost::python::detail::signature_element*
boost::python::detail::signature_arity<0u>::impl<Sig>::elements() [with Sig =
boost::mpl::vector1<const char* const>]â
/usr/include/boost/python/detail/caller.hpp:232:78: required from âstatic
boost::python::detail::py_func_sig_info
boost::python::detail::caller_arity<0u>::impl<F, Policies, Sig>::signature()
[with F = const char* const (*)(); Policies =
boost::python::default_call_policies; Sig = boost::mpl::vector1<const char*
const>]â
/usr/include/boost/python/object/py_function.hpp:48:35: required from
âboost::python::detail::py_func_sig_info
boost::python::objects::caller_py_function_impl<Caller>::signature() const
[with Caller = boost::python::detail::caller<const char* const (*)(),
boost::python::default_call_policies, boost::mpl::vector1<const char* const>
>]â
hello.cpp:10:1: required from here
/usr/include/boost/python/detail/unwind_type.hpp:165:72: error: no matching
function for call to âboost::python::detail::unwind_helper2<1>::execute(const
char* const (*)(), boost::python::converter::detail::unwind_type_id_helper*)â
/usr/include/boost/python/detail/unwind_type.hpp:165:72: note: candidate is:
In file included from
/usr/include/boost/python/converter/pytype_function.hpp:10:0,
from /usr/include/boost/python/to_python_indirect.hpp:16,
from /usr/include/boost/python/converter/arg_to_python.hpp:10,
from /usr/include/boost/python/call.hpp:15,
from /usr/include/boost/python/object_core.hpp:14,
from /usr/include/boost/python/args.hpp:25,
from /usr/include/boost/python.hpp:11,
from hello.cpp:1:
/usr/include/boost/python/detail/unwind_type.hpp:114:5: note: template<class
Generator, class U> static typename Generator::result_type
boost::python::detail::unwind_helper2<1>::execute(U* (*)(), Generator*)
/usr/include/boost/python/detail/unwind_type.hpp:114:5: note: template
argument deduction/substitution failed:
In file included from
/usr/include/boost/python/converter/pytype_function.hpp:10:0,
from /usr/include/boost/python/to_python_indirect.hpp:16,
from /usr/include/boost/python/converter/arg_to_python.hpp:10,
from /usr/include/boost/python/call.hpp:15,
from /usr/include/boost/python/object_core.hpp:14,
from /usr/include/boost/python/args.hpp:25,
from /usr/include/boost/python.hpp:11,
from hello.cpp:1:
/usr/include/boost/python/detail/unwind_type.hpp:165:72: note: types âU*â
and âconst char* constâ have incompatible cv-qualifiers
It looks like the salient error is this one:
/usr/include/boost/python/detail/invoke.hpp:75:19: error: no match for call to
â(const
boost::python::detail::specify_a_return_value_policy_to_wrap_functions_returning<const
char* const>) (const char*)â
but the Boost Python tutorial didn't mention the need to specify a
return value policy for the "hello world" example.
So, I suppose this is either
a) a bug in Boost Python,
b) a bug in the Boost Python tutorial I copied from, or
c) a mistake I'm making
Does anyone see which?
--
J.
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