From uckelman at nomic.net  Thu Jul  5 12:21:32 2012
From: uckelman at nomic.net (Joel Uckelman)
Date: Thu, 05 Jul 2012 03:21:32 -0700
Subject: [C++-sig] errors compiling Boost Python example
Message-ID: <20120705102132.7B6D83618B5@charybdis.ellipsis.cx>

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 ???PyObject* 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]???:
/usr/include/boost/python/detail/caller.hpp:223:13:   required from ???PyObject* 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]???
/usr/include/boost/python/object/py_function.hpp:38:33:   required from ???PyObject* 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]???
hello.cpp:10:1:   required from here
/usr/include/boost/python/detail/invoke.hpp:75:19: error: no match for call to ???(const boost::python::detail::specify_a_return_value_policy_to_wrap_functions_returning<const char* const>) (const char*)???
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 ???static 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]???:
/usr/include/boost/python/detail/caller.hpp:242:13:   required from ???static 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>]???
/usr/include/boost/python/object/py_function.hpp:48:35:   required from ???boost::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> >]???
hello.cpp:10:1:   required from here
/usr/include/boost/python/detail/caller.hpp:102:109: error: ???struct boost::python::detail::specify_a_return_value_policy_to_wrap_functions_returning<const char* const>??? has no member named ???get_pytype???
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 ???typename 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]???:
/usr/include/boost/python/converter/pytype_function.hpp:45:74:   required from ???boost::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>]???
/usr/include/boost/python/converter/pytype_function.hpp:68:13:   required from ???static const PyTypeObject* boost::python::converter::expected_pytype_for_arg<T>::get_pytype() [with T = const char* const; PyTypeObject = _typeobject]???
/usr/include/boost/python/detail/signature.hpp:98:13:   required from ???static const boost::python::detail::signature_element* boost::python::detail::signature_arity<0u>::impl<Sig>::elements() [with Sig = boost::mpl::vector1<const char* const>]???
/usr/include/boost/python/detail/caller.hpp:232:78:   required from ???static 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>]???
/usr/include/boost/python/object/py_function.hpp:48:35:   required from ???boost::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> >]???
hello.cpp:10:1:   required from here
/usr/include/boost/python/detail/unwind_type.hpp:165:72: error: no matching function for call to ???boost::python::detail::unwind_helper2<1>::execute(const char* const (*)(), boost::python::converter::detail::unwind_type_id_helper*)???
/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 ???U*??? and ???const char* const??? 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 ???(const boost::python::detail::specify_a_return_value_policy_to_wrap_functions_returning<const char* const>) (const char*)???

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.

From redetin at gmail.com  Thu Jul  5 12:49:38 2012
From: redetin at gmail.com (Jani Tiainen)
Date: Thu, 05 Jul 2012 13:49:38 +0300
Subject: [C++-sig] Instance ownership transfer in constructor.
Message-ID: <4FF57142.6030507@gmail.com>

Hi,

I'm new to python.boost library and I'm trying to use it to wrap a third 
party library. Everything else I've managed to get working - thanks to 
excellent library and lot of examples I've found around a net.

Only thing I can't get working properly is instance ownership transfer 
in constructor.

So classes in library are defined like follows:

class Owner {
...
}

class Data {
     Data(Owner *owner); // <-- Here happens ownership transfer.
}


Python code is like follows:

owner = Owner()
data_1 = Data(owner)
data_2 = Data(owner)

So when Python script stops runnning it causes crash due the fact that 
I've data objects are automatically destroyed by Owner-class but Python 
deletes them by using Data-class destructor (which shouldn't happen ever).

-- 
Jani Tiainen

- Well planned is half done and a half done has been sufficient before...


From sybren at stuvel.eu  Thu Jul  5 12:55:41 2012
From: sybren at stuvel.eu (=?UTF-8?Q?Sybren_A=2E_St=C3=BCvel?=)
Date: Thu, 5 Jul 2012 12:55:41 +0200
Subject: [C++-sig] errors compiling Boost Python example
In-Reply-To: <20120705102132.7B6D83618B5@charybdis.ellipsis.cx>
References: <20120705102132.7B6D83618B5@charybdis.ellipsis.cx>
Message-ID: <CAAAfPCB_hXqL1eEXAVBFQ=wzOJDmAUZW2hokfSO0qqicFJ9-PA@mail.gmail.com>

Hi Joel,

On 5 July 2012 12:21, Joel Uckelman <uckelman at nomic.net> wrote:

> I'm trying to compile the example from the Boost Python docs without
> success. [...]
>

There are many ways in which you can fix this. I think the easiest one from
an I'm-just-starting-so-please-give-me-a-simple-hello-world-program point
of view is to replace "char const *" with "std::string". That works on my
machine (Python 3.2, VS2010, Boost 1.48).

Best,
-- 
Sybren A. St?vel

http://stuvel.eu/
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From uckelman at nomic.net  Thu Jul  5 13:10:07 2012
From: uckelman at nomic.net (Joel Uckelman)
Date: Thu, 05 Jul 2012 04:10:07 -0700
Subject: [C++-sig] errors compiling Boost Python example
In-Reply-To: <CAAAfPCB_hXqL1eEXAVBFQ=wzOJDmAUZW2hokfSO0qqicFJ9-PA@mail.gmail.com>
References: <20120705102132.7B6D83618B5@charybdis.ellipsis.cx>
	<CAAAfPCB_hXqL1eEXAVBFQ=wzOJDmAUZW2hokfSO0qqicFJ9-PA@mail.gmail.com>
Message-ID: <20120705111007.9C0793618B6@charybdis.ellipsis.cx>

Thus spake Sybren A. St??vel:
> 
> Hi Joel,
> 
> On 5 July 2012 12:21, Joel Uckelman <uckelman at nomic.net> wrote:
> 
> > I'm trying to compile the example from the Boost Python docs without
> > success. [...]
> >
> 
> There are many ways in which you can fix this. I think the easiest one from
> an I'm-just-starting-so-please-give-me-a-simple-hello-world-program point
> of view is to replace "char const *" with "std::string". That works on my
> machine (Python 3.2, VS2010, Boost 1.48).

Yes, I can compile if I switch to std::string as the return type. Thanks
for that.

Do you know why Boost Python complains about returning a char const*?
It's a strange thing to have for the first example in the docs if it
won't compile.
 
-- 
J.

From sybren at stuvel.eu  Thu Jul  5 13:15:42 2012
From: sybren at stuvel.eu (=?UTF-8?Q?Sybren_A=2E_St=C3=BCvel?=)
Date: Thu, 5 Jul 2012 13:15:42 +0200
Subject: [C++-sig] errors compiling Boost Python example
In-Reply-To: <20120705111007.9C0793618B6@charybdis.ellipsis.cx>
References: <20120705102132.7B6D83618B5@charybdis.ellipsis.cx>
	<CAAAfPCB_hXqL1eEXAVBFQ=wzOJDmAUZW2hokfSO0qqicFJ9-PA@mail.gmail.com>
	<20120705111007.9C0793618B6@charybdis.ellipsis.cx>
Message-ID: <CAAAfPCDrBadqXae_y_6D901gDGtwMQUa8K_9PbRaFpEehvMBPg@mail.gmail.com>

On 5 July 2012 13:10, Joel Uckelman <uckelman at nomic.net> wrote:

> Do you know why Boost Python complains about returning a char const*?
>

When returning a pointer, you have to tell Boost::Python what to do with
it. The most important issue is one of ownership. Once the pointer has been
returned as a Python object in the Python world, and that object goes out
of scope, what should happen with the pointer? Is it owned by Python and
should the pointed-to memory be deallocated too? Or was it still owned by
the function that returned it? This is what you have to tell Boost::Python
before it allows you to return pointers. And this is also why I looked for
a solution that didn't involve pointers - much easier to understand as a
first example.


> It's a strange thing to have for the first example in the docs if it won't
> compile.


I agree. Personally I can't do anything about that, though.

-- 
Sybren A. St?vel

http://stuvel.eu/
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From rwgk at google.com  Thu Jul  5 16:57:28 2012
From: rwgk at google.com (Ralf Grosse-Kunstleve)
Date: Thu, 5 Jul 2012 07:57:28 -0700
Subject: [C++-sig] errors compiling Boost Python example
In-Reply-To: <20120705102132.7B6D83618B5@charybdis.ellipsis.cx>
References: <20120705102132.7B6D83618B5@charybdis.ellipsis.cx>
Message-ID: <CADfjg2px2HpXiu5RvhAzt-Uf6hHE726WDSVOsoyrsY_tBd8p0w@mail.gmail.com>

It looks like you inserted an extra const (I don't see it in the current
tutorial) ...

char const * const greet() {

It should work if you remove it.

Ralf


On Thu, Jul 5, 2012 at 3:21 AM, Joel Uckelman <uckelman at nomic.net> wrote:

> 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
> ?PyObject*
> 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]?:
> /usr/include/boost/python/detail/caller.hpp:223:13:   required from
> ?PyObject* 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]?
> /usr/include/boost/python/object/py_function.hpp:38:33:   required from
> ?PyObject*
> 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]?
> hello.cpp:10:1:   required from here
> /usr/include/boost/python/detail/invoke.hpp:75:19: error: no match for
> call to ?(const
> boost::python::detail::specify_a_return_value_policy_to_wrap_functions_returning<const
> char* const>) (const char*)?
> 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 ?static
> 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]?:
> /usr/include/boost/python/detail/caller.hpp:242:13:   required from
> ?static 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>]?
> /usr/include/boost/python/object/py_function.hpp:48:35:   required from
> ?boost::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> >]?
> hello.cpp:10:1:   required from here
> /usr/include/boost/python/detail/caller.hpp:102:109: error: ?struct
> boost::python::detail::specify_a_return_value_policy_to_wrap_functions_returning<const
> char* const>? has no member named ?get_pytype?
> 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
> ?typename 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]?:
> /usr/include/boost/python/converter/pytype_function.hpp:45:74:   required
> from ?boost::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>]?
> /usr/include/boost/python/converter/pytype_function.hpp:68:13:   required
> from ?static const PyTypeObject*
> boost::python::converter::expected_pytype_for_arg<T>::get_pytype() [with T
> = const char* const; PyTypeObject = _typeobject]?
> /usr/include/boost/python/detail/signature.hpp:98:13:   required from
> ?static const boost::python::detail::signature_element*
> boost::python::detail::signature_arity<0u>::impl<Sig>::elements() [with Sig
> = boost::mpl::vector1<const char* const>]?
> /usr/include/boost/python/detail/caller.hpp:232:78:   required from
> ?static 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>]?
> /usr/include/boost/python/object/py_function.hpp:48:35:   required from
> ?boost::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> >]?
> hello.cpp:10:1:   required from here
> /usr/include/boost/python/detail/unwind_type.hpp:165:72: error: no
> matching function for call to
> ?boost::python::detail::unwind_helper2<1>::execute(const char* const (*)(),
> boost::python::converter::detail::unwind_type_id_helper*)?
> /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
> ?U*? and ?const char* const? 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 ?(const
> boost::python::detail::specify_a_return_value_policy_to_wrap_functions_returning<const
> char* const>) (const char*)?
>
> 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.
>
> _______________________________________________
> Cplusplus-sig mailing list
> Cplusplus-sig at python.org
> http://mail.python.org/mailman/listinfo/cplusplus-sig
>
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From rwgk at google.com  Thu Jul  5 16:59:55 2012
From: rwgk at google.com (Ralf Grosse-Kunstleve)
Date: Thu, 5 Jul 2012 07:59:55 -0700
Subject: [C++-sig] errors compiling Boost Python example
In-Reply-To: <CADfjg2px2HpXiu5RvhAzt-Uf6hHE726WDSVOsoyrsY_tBd8p0w@mail.gmail.com>
References: <20120705102132.7B6D83618B5@charybdis.ellipsis.cx>
	<CADfjg2px2HpXiu5RvhAzt-Uf6hHE726WDSVOsoyrsY_tBd8p0w@mail.gmail.com>
Message-ID: <CADfjg2pjqkxGR7A8QY9fu05OF+0o2kEpBno1WkD34BzpHBBTww@mail.gmail.com>

Oops, I meant to mark the extra const with a color:

char const * *const* greet() {


On Thu, Jul 5, 2012 at 7:57 AM, Ralf Grosse-Kunstleve <rwgk at google.com>wrote:

> It looks like you inserted an extra const (I don't see it in the current
> tutorial) ...
>
> char const * const greet() {
>
> It should work if you remove it.
>
> Ralf
>
>
> On Thu, Jul 5, 2012 at 3:21 AM, Joel Uckelman <uckelman at nomic.net> wrote:
>
>> 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
>> ?PyObject*
>> 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]?:
>> /usr/include/boost/python/detail/caller.hpp:223:13:   required from
>> ?PyObject* 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]?
>> /usr/include/boost/python/object/py_function.hpp:38:33:   required from
>> ?PyObject*
>> 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]?
>> hello.cpp:10:1:   required from here
>> /usr/include/boost/python/detail/invoke.hpp:75:19: error: no match for
>> call to ?(const
>> boost::python::detail::specify_a_return_value_policy_to_wrap_functions_returning<const
>> char* const>) (const char*)?
>> 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 ?static
>> 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]?:
>> /usr/include/boost/python/detail/caller.hpp:242:13:   required from
>> ?static 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>]?
>> /usr/include/boost/python/object/py_function.hpp:48:35:   required from
>> ?boost::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> >]?
>> hello.cpp:10:1:   required from here
>> /usr/include/boost/python/detail/caller.hpp:102:109: error: ?struct
>> boost::python::detail::specify_a_return_value_policy_to_wrap_functions_returning<const
>> char* const>? has no member named ?get_pytype?
>> 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
>> ?typename 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]?:
>> /usr/include/boost/python/converter/pytype_function.hpp:45:74:   required
>> from ?boost::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>]?
>> /usr/include/boost/python/converter/pytype_function.hpp:68:13:   required
>> from ?static const PyTypeObject*
>> boost::python::converter::expected_pytype_for_arg<T>::get_pytype() [with T
>> = const char* const; PyTypeObject = _typeobject]?
>> /usr/include/boost/python/detail/signature.hpp:98:13:   required from
>> ?static const boost::python::detail::signature_element*
>> boost::python::detail::signature_arity<0u>::impl<Sig>::elements() [with Sig
>> = boost::mpl::vector1<const char* const>]?
>> /usr/include/boost/python/detail/caller.hpp:232:78:   required from
>> ?static 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>]?
>> /usr/include/boost/python/object/py_function.hpp:48:35:   required from
>> ?boost::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> >]?
>> hello.cpp:10:1:   required from here
>> /usr/include/boost/python/detail/unwind_type.hpp:165:72: error: no
>> matching function for call to
>> ?boost::python::detail::unwind_helper2<1>::execute(const char* const (*)(),
>> boost::python::converter::detail::unwind_type_id_helper*)?
>> /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
>> ?U*? and ?const char* const? 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 ?(const
>> boost::python::detail::specify_a_return_value_policy_to_wrap_functions_returning<const
>> char* const>) (const char*)?
>>
>> 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.
>>
>> _______________________________________________
>> Cplusplus-sig mailing list
>> Cplusplus-sig at python.org
>> http://mail.python.org/mailman/listinfo/cplusplus-sig
>>
>
>
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From uckelman at nomic.net  Thu Jul  5 17:02:33 2012
From: uckelman at nomic.net (Joel Uckelman)
Date: Thu, 05 Jul 2012 08:02:33 -0700
Subject: [C++-sig] errors compiling Boost Python example
In-Reply-To: <CADfjg2px2HpXiu5RvhAzt-Uf6hHE726WDSVOsoyrsY_tBd8p0w@mail.gmail.com>
References: <20120705102132.7B6D83618B5@charybdis.ellipsis.cx>
	<CADfjg2px2HpXiu5RvhAzt-Uf6hHE726WDSVOsoyrsY_tBd8p0w@mail.gmail.com>
Message-ID: <20120705150234.294A23609BE@charybdis.ellipsis.cx>

Thus spake Ralf Grosse-Kunstleve:
> 
> It looks like you inserted an extra const (I don't see it in the current
> tutorial) ...
> 
> char const * const greet() {
> 
> It should work if you remove it.

Ha! You're correct. The example program was so short that I just retyped
it, and I made the pointer const out of habit without noticing. Now all
makes sense. Thanks!
 
-- 
J.

From j.reid at mail.cryst.bbk.ac.uk  Thu Jul  5 18:00:19 2012
From: j.reid at mail.cryst.bbk.ac.uk (John Reid)
Date: Thu, 05 Jul 2012 17:00:19 +0100
Subject: [C++-sig] Instance ownership transfer in constructor.
In-Reply-To: <4FF57142.6030507@gmail.com>
References: <4FF57142.6030507@gmail.com>
Message-ID: <jt4dmj$h44$1@dough.gmane.org>

On 05/07/12 11:49, Jani Tiainen wrote:
> Hi,
> 
> I'm new to python.boost library and I'm trying to use it to wrap a third
> party library. Everything else I've managed to get working - thanks to
> excellent library and lot of examples I've found around a net.
> 
> Only thing I can't get working properly is instance ownership transfer
> in constructor.
> 
> So classes in library are defined like follows:
> 
> class Owner {
> ...
> }
> 
> class Data {
>     Data(Owner *owner); // <-- Here happens ownership transfer.
> }
> 
> 
> Python code is like follows:
> 
> owner = Owner()
> data_1 = Data(owner)
> data_2 = Data(owner)
> 
> So when Python script stops runnning it causes crash due the fact that
> I've data objects are automatically destroyed by Owner-class but Python
> deletes them by using Data-class destructor (which shouldn't happen ever).
> 

If I understand you correctly then you want the owner object to remain
alive at least as long as data_1 and data_2? If so you could use
with_custodian_and_ward:
http://www.boost.org/doc/libs/1_49_0/libs/python/doc/v2/with_custodian_and_ward.html

For example something like the following should work:

        namespace py = boost::python;
	py::class_<
		...
	> my_class(
	    "Data",
	    "docstring.",
            py::init< Owner * >( "Constructor." )[
                py::with_custodian_and_ward< 1, 2 >()
            ]
	);


From redetin at gmail.com  Thu Jul  5 18:47:04 2012
From: redetin at gmail.com (Jani Tiainen)
Date: Thu, 5 Jul 2012 19:47:04 +0300
Subject: [C++-sig] Instance ownership transfer in constructor.
In-Reply-To: <jt4dmj$h44$1@dough.gmane.org>
References: <4FF57142.6030507@gmail.com>
	<jt4dmj$h44$1@dough.gmane.org>
Message-ID: <CAHn91oeKrHPsRueM7kU067N_cgZxG5hj4jNzsL-YecBZG1B6dQ@mail.gmail.com>

I want to do it another way around:

Instance of Owner should hold reference to data_1 and data_2 as long as
owner is alive.

Now following happens:
owner = Owner()
data_1 = Data(owner) # data_1 ownership is transferred to owner object
data_2 = Data(owner) # data_2 ownership is transferred to owner object

print owner.get_data_objects()

<data_1>, <data_2>

del data_1
del data_2

print owner.get_data_objects()
# Crash because data_1 and data_2 are deleted even owner should still hold
the reference.

I tried to do it like
http://www.boost.org/doc/libs/1_49_0/libs/python/test/injected.cpp  but it
didn't worked for me.

On Thu, Jul 5, 2012 at 7:00 PM, John Reid <j.reid at mail.cryst.bbk.ac.uk>wrote:

> On 05/07/12 11:49, Jani Tiainen wrote:
> > Hi,
> >
> > I'm new to python.boost library and I'm trying to use it to wrap a third
> > party library. Everything else I've managed to get working - thanks to
> > excellent library and lot of examples I've found around a net.
> >
> > Only thing I can't get working properly is instance ownership transfer
> > in constructor.
> >
> > So classes in library are defined like follows:
> >
> > class Owner {
> > ...
> > }
> >
> > class Data {
> >     Data(Owner *owner); // <-- Here happens ownership transfer.
> > }
> >
> >
> > Python code is like follows:
> >
> > owner = Owner()
> > data_1 = Data(owner)
> > data_2 = Data(owner)
> >
> > So when Python script stops runnning it causes crash due the fact that
> > I've data objects are automatically destroyed by Owner-class but Python
> > deletes them by using Data-class destructor (which shouldn't happen
> ever).
> >
>
> If I understand you correctly then you want the owner object to remain
> alive at least as long as data_1 and data_2? If so you could use
> with_custodian_and_ward:
>
> http://www.boost.org/doc/libs/1_49_0/libs/python/doc/v2/with_custodian_and_ward.html
>
> For example something like the following should work:
>
>         namespace py = boost::python;
>         py::class_<
>                 ...
>         > my_class(
>             "Data",
>             "docstring.",
>             py::init< Owner * >( "Constructor." )[
>                 py::with_custodian_and_ward< 1, 2 >()
>             ]
>         );
>
> _______________________________________________
> Cplusplus-sig mailing list
> Cplusplus-sig at python.org
> http://mail.python.org/mailman/listinfo/cplusplus-sig
>



-- 
Jani Tiainen

- Well planned is half done, and a half done has been sufficient before...
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From brandsmeier at gmx.de  Thu Jul  5 19:44:54 2012
From: brandsmeier at gmx.de (Holger Brandsmeier)
Date: Thu, 5 Jul 2012 19:44:54 +0200
Subject: [C++-sig] Instance ownership transfer in constructor.
In-Reply-To: <CAHn91oeKrHPsRueM7kU067N_cgZxG5hj4jNzsL-YecBZG1B6dQ@mail.gmail.com>
References: <4FF57142.6030507@gmail.com> <jt4dmj$h44$1@dough.gmane.org>
	<CAHn91oeKrHPsRueM7kU067N_cgZxG5hj4jNzsL-YecBZG1B6dQ@mail.gmail.com>
Message-ID: <CAFP7zVv-BARJ6BrpZoy_0B3QrgF3fiaO=S8gdi4_4fup_Z7oFA@mail.gmail.com>

Jani,

ok what you want to do is quite a lot more intrusive, so you need some
more involved methods, but it should be possible. I would do it by
noting the following
 - data_1 is published to python as a boost::shared_ptr<Data> (default
holder type)
 - usually it is difficult for a class member function, to obtain a
shared_ptr<> to itself, i.e. something like `this` but not of type
Data* but of boost::shared_ptr<Data>.
 - fortunately there is something supported by boost itself, called
`enable_shared_from_this`, see
  http://stackoverflow.com/questions/142391/getting-a-boostshared-ptr-for-this
 - Now you want `owner` to hold on to this `shared_ptr<Data>` which
ensures that `data_1` does not get deleted before `owner`, you can do
this by
  owner->setData( shared_from_this() )
in any member function of `Data`.
 - Note that I _think_ that you are not allowed to use
`shared_from_this()` in the constructor itself, so you might have to
use boost::pythons `make_constructor` to make an ordinary member /
non-member function behave as the constructor in python.

Maybe someone has a quicker way of doing this, but remember that this
is exactly the use case that `shared_ptr` are made for,
Holger


On Thu, Jul 5, 2012 at 6:47 PM, Jani Tiainen <redetin at gmail.com> wrote:
> I want to do it another way around:
>
> Instance of Owner should hold reference to data_1 and data_2 as long as
> owner is alive.
>
> Now following happens:
> owner = Owner()
> data_1 = Data(owner) # data_1 ownership is transferred to owner object
> data_2 = Data(owner) # data_2 ownership is transferred to owner object
>
> print owner.get_data_objects()
>
> <data_1>, <data_2>
>
> del data_1
> del data_2
>
> print owner.get_data_objects()
> # Crash because data_1 and data_2 are deleted even owner should still hold
> the reference.
>
> I tried to do it like
> http://www.boost.org/doc/libs/1_49_0/libs/python/test/injected.cpp  but it
> didn't worked for me.
>
>
> On Thu, Jul 5, 2012 at 7:00 PM, John Reid <j.reid at mail.cryst.bbk.ac.uk>
> wrote:
>>
>> On 05/07/12 11:49, Jani Tiainen wrote:
>> > Hi,
>> >
>> > I'm new to python.boost library and I'm trying to use it to wrap a third
>> > party library. Everything else I've managed to get working - thanks to
>> > excellent library and lot of examples I've found around a net.
>> >
>> > Only thing I can't get working properly is instance ownership transfer
>> > in constructor.
>> >
>> > So classes in library are defined like follows:
>> >
>> > class Owner {
>> > ...
>> > }
>> >
>> > class Data {
>> >     Data(Owner *owner); // <-- Here happens ownership transfer.
>> > }
>> >
>> >
>> > Python code is like follows:
>> >
>> > owner = Owner()
>> > data_1 = Data(owner)
>> > data_2 = Data(owner)
>> >
>> > So when Python script stops runnning it causes crash due the fact that
>> > I've data objects are automatically destroyed by Owner-class but Python
>> > deletes them by using Data-class destructor (which shouldn't happen
>> > ever).
>> >
>>
>> If I understand you correctly then you want the owner object to remain
>> alive at least as long as data_1 and data_2? If so you could use
>> with_custodian_and_ward:
>>
>> http://www.boost.org/doc/libs/1_49_0/libs/python/doc/v2/with_custodian_and_ward.html
>>
>> For example something like the following should work:
>>
>>         namespace py = boost::python;
>>         py::class_<
>>                 ...
>>         > my_class(
>>             "Data",
>>             "docstring.",
>>             py::init< Owner * >( "Constructor." )[
>>                 py::with_custodian_and_ward< 1, 2 >()
>>             ]
>>         );
>>
>> _______________________________________________
>> Cplusplus-sig mailing list
>> Cplusplus-sig at python.org
>> http://mail.python.org/mailman/listinfo/cplusplus-sig
>
>
>
>
> --
> Jani Tiainen
>
> - Well planned is half done, and a half done has been sufficient before...
>
>
> _______________________________________________
> Cplusplus-sig mailing list
> Cplusplus-sig at python.org
> http://mail.python.org/mailman/listinfo/cplusplus-sig

From redetin at gmail.com  Fri Jul  6 08:20:54 2012
From: redetin at gmail.com (Jani Tiainen)
Date: Fri, 06 Jul 2012 09:20:54 +0300
Subject: [C++-sig] Instance ownership transfer in constructor.
In-Reply-To: <CAFP7zVv-BARJ6BrpZoy_0B3QrgF3fiaO=S8gdi4_4fup_Z7oFA@mail.gmail.com>
References: <4FF57142.6030507@gmail.com> <jt4dmj$h44$1@dough.gmane.org>
	<CAHn91oeKrHPsRueM7kU067N_cgZxG5hj4jNzsL-YecBZG1B6dQ@mail.gmail.com>
	<CAFP7zVv-BARJ6BrpZoy_0B3QrgF3fiaO=S8gdi4_4fup_Z7oFA@mail.gmail.com>
Message-ID: <4FF683C6.5080206@gmail.com>

Hi,

I'm still strugling with this whole thingy so I came up with more 
concrete example I'm trying to achieve:

http://pastebin.com/dVRfT56x


And in python code I do like this:

owner = Owner()
data = Data(owner)

After script is finished I get warning message that Data destructor 
shouldn't be called directly. And then python crashes due memory corruption.

I've tried to make usage of shared_ptr but no luck and I didn't 
understood how to apply shared_ptr_for_this.

(NOTE: in my case all classes are from 3rd party library that I have no 
control over)

5.7.2012 20:44, Holger Brandsmeier kirjoitti:
> Jani,
>
> ok what you want to do is quite a lot more intrusive, so you need some
> more involved methods, but it should be possible. I would do it by
> noting the following
>   - data_1 is published to python as a boost::shared_ptr<Data> (default
> holder type)
>   - usually it is difficult for a class member function, to obtain a
> shared_ptr<> to itself, i.e. something like `this` but not of type
> Data* but of boost::shared_ptr<Data>.
>   - fortunately there is something supported by boost itself, called
> `enable_shared_from_this`, see
>    http://stackoverflow.com/questions/142391/getting-a-boostshared-ptr-for-this
>   - Now you want `owner` to hold on to this `shared_ptr<Data>` which
> ensures that `data_1` does not get deleted before `owner`, you can do
> this by
>    owner->setData( shared_from_this() )
> in any member function of `Data`.
>   - Note that I _think_ that you are not allowed to use
> `shared_from_this()` in the constructor itself, so you might have to
> use boost::pythons `make_constructor` to make an ordinary member /
> non-member function behave as the constructor in python.
>
> Maybe someone has a quicker way of doing this, but remember that this
> is exactly the use case that `shared_ptr` are made for,
> Holger
>
>
> On Thu, Jul 5, 2012 at 6:47 PM, Jani Tiainen <redetin at gmail.com> wrote:
>> I want to do it another way around:
>>
>> Instance of Owner should hold reference to data_1 and data_2 as long as
>> owner is alive.
>>
>> Now following happens:
>> owner = Owner()
>> data_1 = Data(owner) # data_1 ownership is transferred to owner object
>> data_2 = Data(owner) # data_2 ownership is transferred to owner object
>>
>> print owner.get_data_objects()
>>
>> <data_1>, <data_2>
>>
>> del data_1
>> del data_2
>>
>> print owner.get_data_objects()
>> # Crash because data_1 and data_2 are deleted even owner should still hold
>> the reference.
>>
>> I tried to do it like
>> http://www.boost.org/doc/libs/1_49_0/libs/python/test/injected.cpp  but it
>> didn't worked for me.
>>
>>
>> On Thu, Jul 5, 2012 at 7:00 PM, John Reid <j.reid at mail.cryst.bbk.ac.uk>
>> wrote:
>>>
>>> On 05/07/12 11:49, Jani Tiainen wrote:
>>>> Hi,
>>>>
>>>> I'm new to python.boost library and I'm trying to use it to wrap a third
>>>> party library. Everything else I've managed to get working - thanks to
>>>> excellent library and lot of examples I've found around a net.
>>>>
>>>> Only thing I can't get working properly is instance ownership transfer
>>>> in constructor.
>>>>
>>>> So classes in library are defined like follows:
>>>>
>>>> class Owner {
>>>> ...
>>>> }
>>>>
>>>> class Data {
>>>>      Data(Owner *owner); // <-- Here happens ownership transfer.
>>>> }
>>>>
>>>>
>>>> Python code is like follows:
>>>>
>>>> owner = Owner()
>>>> data_1 = Data(owner)
>>>> data_2 = Data(owner)
>>>>
>>>> So when Python script stops runnning it causes crash due the fact that
>>>> I've data objects are automatically destroyed by Owner-class but Python
>>>> deletes them by using Data-class destructor (which shouldn't happen
>>>> ever).
>>>>
>>>
>>> If I understand you correctly then you want the owner object to remain
>>> alive at least as long as data_1 and data_2? If so you could use
>>> with_custodian_and_ward:
>>>
>>> http://www.boost.org/doc/libs/1_49_0/libs/python/doc/v2/with_custodian_and_ward.html
>>>
>>> For example something like the following should work:
>>>
>>>          namespace py = boost::python;
>>>          py::class_<
>>>                  ...
>>>          > my_class(
>>>              "Data",
>>>              "docstring.",
>>>              py::init< Owner * >( "Constructor." )[
>>>                  py::with_custodian_and_ward< 1, 2 >()
>>>              ]
>>>          );
>>>
>>> _______________________________________________
>>> Cplusplus-sig mailing list
>>> Cplusplus-sig at python.org
>>> http://mail.python.org/mailman/listinfo/cplusplus-sig
>>
>>
>>
>>
>> --
>> Jani Tiainen
>>
>> - Well planned is half done, and a half done has been sufficient before...
>>
>>
>> _______________________________________________
>> Cplusplus-sig mailing list
>> Cplusplus-sig at python.org
>> http://mail.python.org/mailman/listinfo/cplusplus-sig
> _______________________________________________
> Cplusplus-sig mailing list
> Cplusplus-sig at python.org
> http://mail.python.org/mailman/listinfo/cplusplus-sig
>


-- 
Jani Tiainen

- Well planned is half done and a half done has been sufficient before...



From brandsmeier at gmx.de  Fri Jul  6 11:57:09 2012
From: brandsmeier at gmx.de (Holger Brandsmeier)
Date: Fri, 6 Jul 2012 11:57:09 +0200
Subject: [C++-sig] Instance ownership transfer in constructor.
In-Reply-To: <4FF683C6.5080206@gmail.com>
References: <4FF57142.6030507@gmail.com> <jt4dmj$h44$1@dough.gmane.org>
	<CAHn91oeKrHPsRueM7kU067N_cgZxG5hj4jNzsL-YecBZG1B6dQ@mail.gmail.com>
	<CAFP7zVv-BARJ6BrpZoy_0B3QrgF3fiaO=S8gdi4_4fup_Z7oFA@mail.gmail.com>
	<4FF683C6.5080206@gmail.com>
Message-ID: <CAFP7zVvfa0=bAmk9F-eRCBb_dUzgYmM0Vs39GCBQaO2vd+gVFQ@mail.gmail.com>

Jani,

can you try what John Reid proposed but instead of
          py::with_custodian_and_ward< 1, 2 >()
please try to use
          py::with_custodian_and_ward< 2, 1 >()
or (more likely to work)
          py::with_custodian_and_ward_postcall< 2, 1 >()

This should bind the lifetime of `self` to its first argument. I just
never tried if this is a legal thing to do in the constructor.

-Holger

On Fri, Jul 6, 2012 at 8:20 AM, Jani Tiainen <redetin at gmail.com> wrote:
> Hi,
>
> I'm still strugling with this whole thingy so I came up with more concrete
> example I'm trying to achieve:
>
> http://pastebin.com/dVRfT56x
>
>
> And in python code I do like this:
>
> owner = Owner()
> data = Data(owner)
>
> After script is finished I get warning message that Data destructor
> shouldn't be called directly. And then python crashes due memory corruption.
>
> I've tried to make usage of shared_ptr but no luck and I didn't understood
> how to apply shared_ptr_for_this.
>
> (NOTE: in my case all classes are from 3rd party library that I have no
> control over)
>
> 5.7.2012 20:44, Holger Brandsmeier kirjoitti:
>
>> Jani,
>>
>> ok what you want to do is quite a lot more intrusive, so you need some
>> more involved methods, but it should be possible. I would do it by
>> noting the following
>>   - data_1 is published to python as a boost::shared_ptr<Data> (default
>> holder type)
>>   - usually it is difficult for a class member function, to obtain a
>> shared_ptr<> to itself, i.e. something like `this` but not of type
>> Data* but of boost::shared_ptr<Data>.
>>   - fortunately there is something supported by boost itself, called
>> `enable_shared_from_this`, see
>>
>> http://stackoverflow.com/questions/142391/getting-a-boostshared-ptr-for-this
>>   - Now you want `owner` to hold on to this `shared_ptr<Data>` which
>> ensures that `data_1` does not get deleted before `owner`, you can do
>> this by
>>    owner->setData( shared_from_this() )
>> in any member function of `Data`.
>>   - Note that I _think_ that you are not allowed to use
>> `shared_from_this()` in the constructor itself, so you might have to
>> use boost::pythons `make_constructor` to make an ordinary member /
>> non-member function behave as the constructor in python.
>>
>> Maybe someone has a quicker way of doing this, but remember that this
>> is exactly the use case that `shared_ptr` are made for,
>> Holger
>>
>>
>> On Thu, Jul 5, 2012 at 6:47 PM, Jani Tiainen <redetin at gmail.com> wrote:
>>>
>>> I want to do it another way around:
>>>
>>> Instance of Owner should hold reference to data_1 and data_2 as long as
>>> owner is alive.
>>>
>>> Now following happens:
>>> owner = Owner()
>>> data_1 = Data(owner) # data_1 ownership is transferred to owner object
>>> data_2 = Data(owner) # data_2 ownership is transferred to owner object
>>>
>>> print owner.get_data_objects()
>>>
>>> <data_1>, <data_2>
>>>
>>> del data_1
>>> del data_2
>>>
>>> print owner.get_data_objects()
>>> # Crash because data_1 and data_2 are deleted even owner should still
>>> hold
>>> the reference.
>>>
>>> I tried to do it like
>>> http://www.boost.org/doc/libs/1_49_0/libs/python/test/injected.cpp  but
>>> it
>>> didn't worked for me.
>>>
>>>
>>> On Thu, Jul 5, 2012 at 7:00 PM, John Reid <j.reid at mail.cryst.bbk.ac.uk>
>>> wrote:
>>>>
>>>>
>>>> On 05/07/12 11:49, Jani Tiainen wrote:
>>>>>
>>>>> Hi,
>>>>>
>>>>> I'm new to python.boost library and I'm trying to use it to wrap a
>>>>> third
>>>>> party library. Everything else I've managed to get working - thanks to
>>>>> excellent library and lot of examples I've found around a net.
>>>>>
>>>>> Only thing I can't get working properly is instance ownership transfer
>>>>> in constructor.
>>>>>
>>>>> So classes in library are defined like follows:
>>>>>
>>>>> class Owner {
>>>>> ...
>>>>> }
>>>>>
>>>>> class Data {
>>>>>      Data(Owner *owner); // <-- Here happens ownership transfer.
>>>>> }
>>>>>
>>>>>
>>>>> Python code is like follows:
>>>>>
>>>>> owner = Owner()
>>>>> data_1 = Data(owner)
>>>>> data_2 = Data(owner)
>>>>>
>>>>> So when Python script stops runnning it causes crash due the fact that
>>>>> I've data objects are automatically destroyed by Owner-class but Python
>>>>> deletes them by using Data-class destructor (which shouldn't happen
>>>>> ever).
>>>>>
>>>>
>>>> If I understand you correctly then you want the owner object to remain
>>>> alive at least as long as data_1 and data_2? If so you could use
>>>> with_custodian_and_ward:
>>>>
>>>>
>>>> http://www.boost.org/doc/libs/1_49_0/libs/python/doc/v2/with_custodian_and_ward.html
>>>>
>>>> For example something like the following should work:
>>>>
>>>>          namespace py = boost::python;
>>>>          py::class_<
>>>>                  ...
>>>>          > my_class(
>>>>              "Data",
>>>>              "docstring.",
>>>>              py::init< Owner * >( "Constructor." )[
>>>>                  py::with_custodian_and_ward< 1, 2 >()
>>>>              ]
>>>>          );
>>>>
>>>> _______________________________________________
>>>> Cplusplus-sig mailing list
>>>> Cplusplus-sig at python.org
>>>> http://mail.python.org/mailman/listinfo/cplusplus-sig
>>>
>>>
>>>
>>>
>>>
>>> --
>>> Jani Tiainen
>>>
>>> - Well planned is half done, and a half done has been sufficient
>>> before...
>>>
>>>
>>> _______________________________________________
>>> Cplusplus-sig mailing list
>>> Cplusplus-sig at python.org
>>> http://mail.python.org/mailman/listinfo/cplusplus-sig
>>
>> _______________________________________________
>> Cplusplus-sig mailing list
>> Cplusplus-sig at python.org
>> http://mail.python.org/mailman/listinfo/cplusplus-sig
>>
>
>
> --
> Jani Tiainen
>
> - Well planned is half done and a half done has been sufficient before...
>
>
>
> _______________________________________________
> Cplusplus-sig mailing list
> Cplusplus-sig at python.org
> http://mail.python.org/mailman/listinfo/cplusplus-sig

From redetin at gmail.com  Fri Jul  6 12:16:06 2012
From: redetin at gmail.com (Jani Tiainen)
Date: Fri, 06 Jul 2012 13:16:06 +0300
Subject: [C++-sig] Instance ownership transfer in constructor.
In-Reply-To: <CAFP7zVvfa0=bAmk9F-eRCBb_dUzgYmM0Vs39GCBQaO2vd+gVFQ@mail.gmail.com>
References: <4FF57142.6030507@gmail.com> <jt4dmj$h44$1@dough.gmane.org>
	<CAHn91oeKrHPsRueM7kU067N_cgZxG5hj4jNzsL-YecBZG1B6dQ@mail.gmail.com>
	<CAFP7zVv-BARJ6BrpZoy_0B3QrgF3fiaO=S8gdi4_4fup_Z7oFA@mail.gmail.com>
	<4FF683C6.5080206@gmail.com>
	<CAFP7zVvfa0=bAmk9F-eRCBb_dUzgYmM0Vs39GCBQaO2vd+gVFQ@mail.gmail.com>
Message-ID: <4FF6BAE6.5090503@gmail.com>

Ok, last suggestions were closest I could get: Now I see that data is 
deleted within owner destructor but still I get error messages that data 
objects are being deleted directly second time by Python.

So now I need some way to say to python that "data" classes are not 
meant to be deleted by python ever.

6.7.2012 12:57, Holger Brandsmeier kirjoitti:
> Jani,
>
> can you try what John Reid proposed but instead of
>            py::with_custodian_and_ward< 1, 2 >()
> please try to use
>            py::with_custodian_and_ward< 2, 1 >()
> or (more likely to work)
>            py::with_custodian_and_ward_postcall< 2, 1 >()
>
> This should bind the lifetime of `self` to its first argument. I just
> never tried if this is a legal thing to do in the constructor.
>
> -Holger
>
> On Fri, Jul 6, 2012 at 8:20 AM, Jani Tiainen <redetin at gmail.com> wrote:
>> Hi,
>>
>> I'm still strugling with this whole thingy so I came up with more concrete
>> example I'm trying to achieve:
>>
>> http://pastebin.com/dVRfT56x
>>
>>
>> And in python code I do like this:
>>
>> owner = Owner()
>> data = Data(owner)
>>
>> After script is finished I get warning message that Data destructor
>> shouldn't be called directly. And then python crashes due memory corruption.
>>
>> I've tried to make usage of shared_ptr but no luck and I didn't understood
>> how to apply shared_ptr_for_this.
>>
>> (NOTE: in my case all classes are from 3rd party library that I have no
>> control over)
>>
>> 5.7.2012 20:44, Holger Brandsmeier kirjoitti:
>>
>>> Jani,
>>>
>>> ok what you want to do is quite a lot more intrusive, so you need some
>>> more involved methods, but it should be possible. I would do it by
>>> noting the following
>>>    - data_1 is published to python as a boost::shared_ptr<Data> (default
>>> holder type)
>>>    - usually it is difficult for a class member function, to obtain a
>>> shared_ptr<> to itself, i.e. something like `this` but not of type
>>> Data* but of boost::shared_ptr<Data>.
>>>    - fortunately there is something supported by boost itself, called
>>> `enable_shared_from_this`, see
>>>
>>> http://stackoverflow.com/questions/142391/getting-a-boostshared-ptr-for-this
>>>    - Now you want `owner` to hold on to this `shared_ptr<Data>` which
>>> ensures that `data_1` does not get deleted before `owner`, you can do
>>> this by
>>>     owner->setData( shared_from_this() )
>>> in any member function of `Data`.
>>>    - Note that I _think_ that you are not allowed to use
>>> `shared_from_this()` in the constructor itself, so you might have to
>>> use boost::pythons `make_constructor` to make an ordinary member /
>>> non-member function behave as the constructor in python.
>>>
>>> Maybe someone has a quicker way of doing this, but remember that this
>>> is exactly the use case that `shared_ptr` are made for,
>>> Holger
>>>
>>>
>>> On Thu, Jul 5, 2012 at 6:47 PM, Jani Tiainen <redetin at gmail.com> wrote:
>>>>
>>>> I want to do it another way around:
>>>>
>>>> Instance of Owner should hold reference to data_1 and data_2 as long as
>>>> owner is alive.
>>>>
>>>> Now following happens:
>>>> owner = Owner()
>>>> data_1 = Data(owner) # data_1 ownership is transferred to owner object
>>>> data_2 = Data(owner) # data_2 ownership is transferred to owner object
>>>>
>>>> print owner.get_data_objects()
>>>>
>>>> <data_1>, <data_2>
>>>>
>>>> del data_1
>>>> del data_2
>>>>
>>>> print owner.get_data_objects()
>>>> # Crash because data_1 and data_2 are deleted even owner should still
>>>> hold
>>>> the reference.
>>>>
>>>> I tried to do it like
>>>> http://www.boost.org/doc/libs/1_49_0/libs/python/test/injected.cpp  but
>>>> it
>>>> didn't worked for me.
>>>>
>>>>
>>>> On Thu, Jul 5, 2012 at 7:00 PM, John Reid <j.reid at mail.cryst.bbk.ac.uk>
>>>> wrote:
>>>>>
>>>>>
>>>>> On 05/07/12 11:49, Jani Tiainen wrote:
>>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> I'm new to python.boost library and I'm trying to use it to wrap a
>>>>>> third
>>>>>> party library. Everything else I've managed to get working - thanks to
>>>>>> excellent library and lot of examples I've found around a net.
>>>>>>
>>>>>> Only thing I can't get working properly is instance ownership transfer
>>>>>> in constructor.
>>>>>>
>>>>>> So classes in library are defined like follows:
>>>>>>
>>>>>> class Owner {
>>>>>> ...
>>>>>> }
>>>>>>
>>>>>> class Data {
>>>>>>       Data(Owner *owner); // <-- Here happens ownership transfer.
>>>>>> }
>>>>>>
>>>>>>
>>>>>> Python code is like follows:
>>>>>>
>>>>>> owner = Owner()
>>>>>> data_1 = Data(owner)
>>>>>> data_2 = Data(owner)
>>>>>>
>>>>>> So when Python script stops runnning it causes crash due the fact that
>>>>>> I've data objects are automatically destroyed by Owner-class but Python
>>>>>> deletes them by using Data-class destructor (which shouldn't happen
>>>>>> ever).
>>>>>>
>>>>>
>>>>> If I understand you correctly then you want the owner object to remain
>>>>> alive at least as long as data_1 and data_2? If so you could use
>>>>> with_custodian_and_ward:
>>>>>
>>>>>
>>>>> http://www.boost.org/doc/libs/1_49_0/libs/python/doc/v2/with_custodian_and_ward.html
>>>>>
>>>>> For example something like the following should work:
>>>>>
>>>>>           namespace py = boost::python;
>>>>>           py::class_<
>>>>>                   ...
>>>>>           > my_class(
>>>>>               "Data",
>>>>>               "docstring.",
>>>>>               py::init< Owner * >( "Constructor." )[
>>>>>                   py::with_custodian_and_ward< 1, 2 >()
>>>>>               ]
>>>>>           );
>>>>>
>>>>> _______________________________________________
>>>>> Cplusplus-sig mailing list
>>>>> Cplusplus-sig at python.org
>>>>> http://mail.python.org/mailman/listinfo/cplusplus-sig
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Jani Tiainen
>>>>
>>>> - Well planned is half done, and a half done has been sufficient
>>>> before...
>>>>
>>>>
>>>> _______________________________________________
>>>> Cplusplus-sig mailing list
>>>> Cplusplus-sig at python.org
>>>> http://mail.python.org/mailman/listinfo/cplusplus-sig
>>>
>>> _______________________________________________
>>> Cplusplus-sig mailing list
>>> Cplusplus-sig at python.org
>>> http://mail.python.org/mailman/listinfo/cplusplus-sig
>>>
>>
>>
>> --
>> Jani Tiainen
>>
>> - Well planned is half done and a half done has been sufficient before...
>>
>>
>>
>> _______________________________________________
>> Cplusplus-sig mailing list
>> Cplusplus-sig at python.org
>> http://mail.python.org/mailman/listinfo/cplusplus-sig
> _______________________________________________
> Cplusplus-sig mailing list
> Cplusplus-sig at python.org
> http://mail.python.org/mailman/listinfo/cplusplus-sig
>


-- 
Jani Tiainen

- Well planned is half done and a half done has been sufficient before...



From herzog at mpi-cbg.de  Wed Jul 18 11:36:33 2012
From: herzog at mpi-cbg.de (Ronny Herzog)
Date: Wed, 18 Jul 2012 11:36:33 +0200
Subject: [C++-sig] boost python/example/quickstart does not work
Message-ID: <ju6032$d0h$1@dough.gmane.org>

Dear all,

I am experiencing a problem with the quickstart example from boost for 
Python. This is what happens:
 >>>
c:\boost_1_50_0\libs\python\example\quickstart>bjam --toolset=msvc 
--verbose-test test
...patience...
...patience...
...found 1652 targets...
...updating 4 targets...
msvc.link bin\test_embed.test\msvc-9.0\debug\threading-multi\test_embed.exe
LINK : warning LNK4001: no object files specified; libraries used
LINK : error LNK2001: unresolved external symbol _mainCRTStartup
bin\test_embed.test\msvc-9.0\debug\threading-multi\test_embed.exe : 
fatal error
LNK1120: 1 unresolved externals

         call "C:\Program Files\Microsoft Visual Studio 
9.0\VC\vcvarsall.bat" x86
  >nul
link /NOLOGO /INCREMENTAL:NO /DEBUG /MACHINE:X86 /subsystem:console 
/out:"bin\te
st_embed.test\msvc-9.0\debug\threading-multi\test_embed.exe" 
/LIBPATH:"c:\Python
26\libs" 
@"bin\test_embed.test\msvc-9.0\debug\threading-multi\test_embed.exe.rs
p"
         if %ERRORLEVEL% NEQ 0 EXIT %ERRORLEVEL%

...failed msvc.link 
bin\test_embed.test\msvc-9.0\debug\threading-multi\test_embe
d.exe bin\test_embed.test\msvc-9.0\debug\threading-multi\test_embed.pdb...
...removing 
bin\test_embed.test\msvc-9.0\debug\threading-multi\test_embed.pdb
...skipped 
<pbin\test_embed.test\msvc-9.0\debug\threading-multi>test_embed.run f
or lack of 
<pbin\test_embed.test\msvc-9.0\debug\threading-multi>test_embed.exe..
.
...failed updating 2 targets...
...skipped 2 targets...
<<<

It somehow does not find the vcvarsall.bat although it is right in the 
place. I even started it before I run bjam.

Any help is appriciated.

Ronny


From innosam at gmail.com  Thu Jul 19 06:10:05 2012
From: innosam at gmail.com (Harkirat Singh)
Date: Thu, 19 Jul 2012 09:40:05 +0530
Subject: [C++-sig] unable to build boost.python with gcc 3.3.5 and python2.4
 : compilation error
Message-ID: <CAM7Xhr+dXVcBkYfuy3=8txENoJ7YVydGb9Mbs_V5sh0J1r+s5Q@mail.gmail.com>

While compiling boost.python particularly, i get this error. Is there any
workaround on this.


*
In file included from boost/unordered/detail/emplace_args.hpp:16,

from boost/unordered/detail/allocator_helpers.hpp:18, from
boost/unordered/unordered_set.hpp:17, from boost/unordered_set.hpp:16,
from boost/graph/adjacency_list.hpp:21, from
libs/python/src/object/inheritance.cpp:11:

boost/move/move.hpp:124: warning: all member functions in class `

boost::move_detail::is_convertible<T, U>' are private

boost/move/move.hpp:254: warning: `class boost::rv<T>' only defines a
private

destructor and has no friends

In file included from boost/range/size.hpp:21,

from boost/range/functions.hpp:20, from
boost/range/iterator_range_core.hpp:26, from
boost/range/iterator_range.hpp:13, from boost/range/irange.hpp:16,
from boost/graph/detail/adjacency_list.hpp:20, from
boost/graph/adjacency_list.hpp:337, from
libs/python/src/object/inheritance.cpp:11:

boost/range/size_type.hpp:41: warning: all member functions in class `

boost::detail::has_size_type<T>' are private

libs/python/src/object/inheritance.cpp:114: sorry, unimplemented: use of `

enumeral_type' in template type unification
*


Regards
Harkirat Singh
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From s_sourceforge at nedprod.com  Thu Jul 19 12:51:51 2012
From: s_sourceforge at nedprod.com (Niall Douglas)
Date: Thu, 19 Jul 2012 11:51:51 +0100
Subject: [C++-sig] unable to build boost.python with gcc 3.3.5 and
	python2.4 : compilation error
In-Reply-To: <CAM7Xhr+dXVcBkYfuy3=8txENoJ7YVydGb9Mbs_V5sh0J1r+s5Q@mail.gmail.com>
References: <CAM7Xhr+dXVcBkYfuy3=8txENoJ7YVydGb9Mbs_V5sh0J1r+s5Q@mail.gmail.com>
Message-ID: <5007E6C7.9175.9C40157@s_sourceforge.nedprod.com>

Use a much older boost, one compatible with an ancient compiler like 
gcc 3.3.5.

Or use a newer gcc.

Niall

On 19 Jul 2012 at 9:40, Harkirat Singh wrote:

> While compiling boost.python particularly, i get this error. Is there any
> workaround on this.
> 
> 
> *
> In file included from boost/unordered/detail/emplace_args.hpp:16,
> 
> from boost/unordered/detail/allocator_helpers.hpp:18, from
> boost/unordered/unordered_set.hpp:17, from boost/unordered_set.hpp:16,
> from boost/graph/adjacency_list.hpp:21, from
> libs/python/src/object/inheritance.cpp:11:
> 
> boost/move/move.hpp:124: warning: all member functions in class `
> 
> boost::move_detail::is_convertible<T, U>' are private
> 
> boost/move/move.hpp:254: warning: `class boost::rv<T>' only defines a
> private
> 
> destructor and has no friends
> 
> In file included from boost/range/size.hpp:21,
> 
> from boost/range/functions.hpp:20, from
> boost/range/iterator_range_core.hpp:26, from
> boost/range/iterator_range.hpp:13, from boost/range/irange.hpp:16,
> from boost/graph/detail/adjacency_list.hpp:20, from
> boost/graph/adjacency_list.hpp:337, from
> libs/python/src/object/inheritance.cpp:11:
> 
> boost/range/size_type.hpp:41: warning: all member functions in class `
> 
> boost::detail::has_size_type<T>' are private
> 
> libs/python/src/object/inheritance.cpp:114: sorry, unimplemented: use of `
> 
> enumeral_type' in template type unification
> *
> 
> 
> Regards
> Harkirat Singh
> 


-- 
Technology & Consulting Services - ned Productions Limited.
http://www.nedproductions.biz/. VAT reg: IE 9708311Q.
Work Portfolio: http://careers.stackoverflow.com/nialldouglas/

From innosam at gmail.com  Thu Jul 19 13:17:00 2012
From: innosam at gmail.com (Harkirat Singh)
Date: Thu, 19 Jul 2012 16:47:00 +0530
Subject: [C++-sig] unable to build boost.python with gcc 3.3.5 and
 python2.4 : compilation error
In-Reply-To: <5007E6C7.9175.9C40157@s_sourceforge.nedprod.com>
References: <CAM7Xhr+dXVcBkYfuy3=8txENoJ7YVydGb9Mbs_V5sh0J1r+s5Q@mail.gmail.com>
	<5007E6C7.9175.9C40157@s_sourceforge.nedprod.com>
Message-ID: <CAM7Xhr+VZgfLkUfRWOX8FfLyyAEupTcA=7g+B8JVxFOL455NXw@mail.gmail.com>

Hi Niall

gcc error is documented: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17327

it would be better if  there is any work around for resolving the
compilation error. Any help would be appreciated.


Alternatively, i built the boost.python library using gcc 4.1.2, that
compiles fine. But the shared object generated couldn't be imported in the
target system.
TARGET SYSTEM:- gcc 3.3.5 and python2.4

    Error:-
    import pyplusplus
    ImportError: /usr/lib/libstdc++.so.6: version `CXXABI_1.3' not found
(required by         ./pyplusplus.so)
Any solution on going in this direction.




On Thu, Jul 19, 2012 at 4:21 PM, Niall Douglas <s_sourceforge at nedprod.com>wrote:

> Use a much older boost, one compatible with an ancient compiler like
> gcc 3.3.5.
>
> Or use a newer gcc.
>
> Niall
>
> On 19 Jul 2012 at 9:40, Harkirat Singh wrote:
>
> > While compiling boost.python particularly, i get this error. Is there any
> > workaround on this.
> >
> >
> > *
> > In file included from boost/unordered/detail/emplace_args.hpp:16,
> >
> > from boost/unordered/detail/allocator_helpers.hpp:18, from
> > boost/unordered/unordered_set.hpp:17, from boost/unordered_set.hpp:16,
> > from boost/graph/adjacency_list.hpp:21, from
> > libs/python/src/object/inheritance.cpp:11:
> >
> > boost/move/move.hpp:124: warning: all member functions in class `
> >
> > boost::move_detail::is_convertible<T, U>' are private
> >
> > boost/move/move.hpp:254: warning: `class boost::rv<T>' only defines a
> > private
> >
> > destructor and has no friends
> >
> > In file included from boost/range/size.hpp:21,
> >
> > from boost/range/functions.hpp:20, from
> > boost/range/iterator_range_core.hpp:26, from
> > boost/range/iterator_range.hpp:13, from boost/range/irange.hpp:16,
> > from boost/graph/detail/adjacency_list.hpp:20, from
> > boost/graph/adjacency_list.hpp:337, from
> > libs/python/src/object/inheritance.cpp:11:
> >
> > boost/range/size_type.hpp:41: warning: all member functions in class `
> >
> > boost::detail::has_size_type<T>' are private
> >
> > libs/python/src/object/inheritance.cpp:114: sorry, unimplemented: use of
> `
> >
> > enumeral_type' in template type unification
> > *
> >
> >
> > Regards
> > Harkirat Singh
> >
>
>
> --
> Technology & Consulting Services - ned Productions Limited.
> http://www.nedproductions.biz/. VAT reg: IE 9708311Q.
> Work Portfolio: http://careers.stackoverflow.com/nialldouglas/
> _______________________________________________
> Cplusplus-sig mailing list
> Cplusplus-sig at python.org
> http://mail.python.org/mailman/listinfo/cplusplus-sig
>



-- 
Harkirat Singh
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From herzog at mpi-cbg.de  Fri Jul 20 16:55:34 2012
From: herzog at mpi-cbg.de (Ronny Herzog)
Date: Fri, 20 Jul 2012 16:55:34 +0200
Subject: [C++-sig] exporting a boost::python::dict containing a
	boost::python::list
Message-ID: <jubrh8$ksc$1@dough.gmane.org>

Dear all,

I want to export a boost::python::dict containing a boost::python::list. 
However, when I print this list in Python, I get an unlimited output of 
some strange numbers:

namespace bp = boost::python;

class readraw
{
....

		bp::list mk_pyPeak_list()
		{
			bp::list py_peak_list;
			for (int i = 0; i < peak_number; i++)
			{
				py_peak_list.append(bp::make_tuple(peak_list[0][i].mz, 
peak_list[0][i].intensity));
			}
			return py_peak_list;
		}

		bp::dict peak_list_info()
		{
			bp::dict info;
			//bp::object pn = peak_number;
			//info["peakNumber"] = peak_number;
			//std::cout << bp::extract<int>(mk_pyPeak_list().attr("__len__")();
			bp::list l(mk_pyPeak_list());
			info["peakList"] = l;

			return info;
		}
	};

BOOST_PYTHON_MODULE(readraw)
{
	bp::class_<readraw>("readraw", bp::init<int>())
		.def("add_peak", &readraw::add_peak)
		.def("peak_list_info", &readraw::peak_list_info)
		.def("average_scans", &readraw::average_scans)
		;

In Python:
 >>> print rawfilereader.peak_list_info()

Results in smth. like:
...
  (-431602080.0, -6.2774385622041925e+66), (-431602080.0, 
-6.2774385622041925e+66
), (-431602080.0, -6.2774385622041925e+66), (-431602080.0, 
-6.2774385622041925e+
66), (-431602080.0, -6.2774385622041925e+66), (-431602080.0, 
-6.2774385622041925
e+66), (-431602080.0, -6.2774385622041925e+66), (-431602080.0, 
-6.27743856220419
25e+66), (-431602080.0, -6.2774385622041925e+66), (-431602080.0, 
-6.277438562204
1925e+66), (-431602080.0, -6.2774385622041925e+66), (-431602080.0, 
-6.2774385622
041925e+66), (-431602080.0, -6.2774385622041925e+66), (-431602080.0, 
-6.27743856
...

What am I doing wrong?

Thanks for the help,
Ronny


From rwgk at google.com  Fri Jul 20 17:19:59 2012
From: rwgk at google.com (Ralf Grosse-Kunstleve)
Date: Fri, 20 Jul 2012 08:19:59 -0700
Subject: [C++-sig] exporting a boost::python::dict containing a
	boost::python::list
In-Reply-To: <jubrh8$ksc$1@dough.gmane.org>
References: <jubrh8$ksc$1@dough.gmane.org>
Message-ID: <CADfjg2pRftch=0sKE6Q_vNwirV+a3joUXSo+VP0=SeL78Z-3rg@mail.gmail.com>

without having looked at your code ...

most likely this is a memory issue. run with valgrind (valgrind.org or man
valgrind) to pin-point the problem.

On Fri, Jul 20, 2012 at 7:55 AM, Ronny Herzog <herzog at mpi-cbg.de> wrote:

>
> Dear all,
>
> I want to export a boost::python::dict containing a boost::python::list.
> However, when I print this list in Python, I get an unlimited output of
> some strange numbers:
>
> namespace bp = boost::python;
>
> class readraw
> {
> ....
>
>                 bp::list mk_pyPeak_list()
>                 {
>                         bp::list py_peak_list;
>                         for (int i = 0; i < peak_number; i++)
>                         {
>                                 py_peak_list.append(bp::make_**tuple(peak_list[0][i].mz,
> peak_list[0][i].intensity));
>                         }
>                         return py_peak_list;
>                 }
>
>                 bp::dict peak_list_info()
>                 {
>                         bp::dict info;
>                         //bp::object pn = peak_number;
>                         //info["peakNumber"] = peak_number;
>                         //std::cout << bp::extract<int>(mk_pyPeak_**
> list().attr("__len__")();
>                         bp::list l(mk_pyPeak_list());
>                         info["peakList"] = l;
>
>                         return info;
>                 }
>         };
>
> BOOST_PYTHON_MODULE(readraw)
> {
>         bp::class_<readraw>("readraw", bp::init<int>())
>                 .def("add_peak", &readraw::add_peak)
>                 .def("peak_list_info", &readraw::peak_list_info)
>                 .def("average_scans", &readraw::average_scans)
>                 ;
>
> In Python:
> >>> print rawfilereader.peak_list_info()
>
> Results in smth. like:
> ...
>  (-431602080.0, -6.2774385622041925e+66), (-431602080.0,
> -6.2774385622041925e+66
> ), (-431602080.0, -6.2774385622041925e+66), (-431602080.0,
> -6.2774385622041925e+
> 66), (-431602080.0, -6.2774385622041925e+66), (-431602080.0,
> -6.2774385622041925
> e+66), (-431602080.0, -6.2774385622041925e+66), (-431602080.0,
> -6.27743856220419
> 25e+66), (-431602080.0, -6.2774385622041925e+66), (-431602080.0,
> -6.277438562204
> 1925e+66), (-431602080.0, -6.2774385622041925e+66), (-431602080.0,
> -6.2774385622
> 041925e+66), (-431602080.0, -6.2774385622041925e+66), (-431602080.0,
> -6.27743856
> ...
>
> What am I doing wrong?
>
> Thanks for the help,
> Ronny
>
> ______________________________**_________________
> Cplusplus-sig mailing list
> Cplusplus-sig at python.org
> http://mail.python.org/**mailman/listinfo/cplusplus-sig<http://mail.python.org/mailman/listinfo/cplusplus-sig>
>
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From herzog at mpi-cbg.de  Sat Jul 21 11:25:30 2012
From: herzog at mpi-cbg.de (Ronny Herzog)
Date: Sat, 21 Jul 2012 11:25:30 +0200
Subject: [C++-sig] exporting a boost::python::dict containing a
	boost::python::list
In-Reply-To: <CADfjg2pRftch=0sKE6Q_vNwirV+a3joUXSo+VP0=SeL78Z-3rg@mail.gmail.com>
References: <jubrh8$ksc$1@dough.gmane.org>
	<CADfjg2pRftch=0sKE6Q_vNwirV+a3joUXSo+VP0=SeL78Z-3rg@mail.gmail.com>
Message-ID: <judsic$9cp$1@dough.gmane.org>

Thanks for the answer, but I should add that I am using Windows 7 32Bit 
with Python 2.6.

Ronny

Am 7/20/2012 5:19 PM, schrieb Ralf Grosse-Kunstleve:
> without having looked at your code ...
>
> most likely this is a memory issue. run with valgrind (valgrind.org
> <http://valgrind.org> or man valgrind) to pin-point the problem.
>
> On Fri, Jul 20, 2012 at 7:55 AM, Ronny Herzog <herzog at mpi-cbg.de
> <mailto:herzog at mpi-cbg.de>> wrote:
>
>
>     Dear all,
>
>     I want to export a boost::python::dict containing a
>     boost::python::list. However, when I print this list in Python, I
>     get an unlimited output of some strange numbers:
>
>     namespace bp = boost::python;
>
>     class readraw
>     {
>     ....
>
>                      bp::list mk_pyPeak_list()
>                      {
>                              bp::list py_peak_list;
>                              for (int i = 0; i < peak_number; i++)
>                              {
>
>     py_peak_list.append(bp::make___tuple(peak_list[0][i].mz,
>     peak_list[0][i].intensity));
>                              }
>                              return py_peak_list;
>                      }
>
>                      bp::dict peak_list_info()
>                      {
>                              bp::dict info;
>                              //bp::object pn = peak_number;
>                              //info["peakNumber"] = peak_number;
>                              //std::cout <<
>     bp::extract<int>(mk_pyPeak___list().attr("__len__")();
>                              bp::list l(mk_pyPeak_list());
>                              info["peakList"] = l;
>
>                              return info;
>                      }
>              };
>
>     BOOST_PYTHON_MODULE(readraw)
>     {
>              bp::class_<readraw>("readraw", bp::init<int>())
>                      .def("add_peak", &readraw::add_peak)
>                      .def("peak_list_info", &readraw::peak_list_info)
>                      .def("average_scans", &readraw::average_scans)
>                      ;
>
>     In Python:
>      >>> print rawfilereader.peak_list_info()
>
>     Results in smth. like:
>     ...
>     (-431602080.0 <tel:%28-431602080.0>, -6.2774385622041925e+66),
>     (-431602080.0 <tel:%28-431602080.0>, -6.2774385622041925e+66
>     ), (-431602080.0 <tel:%28-431602080.0>, -6.2774385622041925e+66),
>     (-431602080.0 <tel:%28-431602080.0>, -6.2774385622041925e+
>     66), (-431602080.0 <tel:%28-431602080.0>, -6.2774385622041925e+66),
>     (-431602080.0 <tel:%28-431602080.0>, -6.2774385622041925
>     e+66), (-431602080.0 <tel:%28-431602080.0>,
>     -6.2774385622041925e+66), (-431602080.0 <tel:%28-431602080.0>,
>     -6.27743856220419
>     25e+66), (-431602080.0 <tel:%28-431602080.0>,
>     -6.2774385622041925e+66), (-431602080.0 <tel:%28-431602080.0>,
>     -6.277438562204
>     1925e+66), (-431602080.0 <tel:%28-431602080.0>,
>     -6.2774385622041925e+66), (-431602080.0 <tel:%28-431602080.0>,
>     -6.2774385622
>     041925e+66), (-431602080.0 <tel:%28-431602080.0>,
>     -6.2774385622041925e+66), (-431602080.0 <tel:%28-431602080.0>,
>     -6.27743856
>     ...
>
>     What am I doing wrong?
>
>     Thanks for the help,
>     Ronny
>
>     _________________________________________________
>     Cplusplus-sig mailing list
>     Cplusplus-sig at python.org <mailto:Cplusplus-sig at python.org>
>     http://mail.python.org/__mailman/listinfo/cplusplus-sig
>     <http://mail.python.org/mailman/listinfo/cplusplus-sig>
>
>
>
>
> _______________________________________________
> Cplusplus-sig mailing list
> Cplusplus-sig at python.org
> http://mail.python.org/mailman/listinfo/cplusplus-sig
>



From herzog at mpi-cbg.de  Sat Jul 21 11:36:38 2012
From: herzog at mpi-cbg.de (Ronny Herzog)
Date: Sat, 21 Jul 2012 11:36:38 +0200
Subject: [C++-sig] exporting a boost::python::dict containing a
	boost::python::list
In-Reply-To: <CADfjg2pRftch=0sKE6Q_vNwirV+a3joUXSo+VP0=SeL78Z-3rg@mail.gmail.com>
References: <jubrh8$ksc$1@dough.gmane.org>
	<CADfjg2pRftch=0sKE6Q_vNwirV+a3joUXSo+VP0=SeL78Z-3rg@mail.gmail.com>
Message-ID: <judt79$den$1@dough.gmane.org>

Thanks again, you were 100% right. I could spot the problem.

Ronny

Am 7/20/2012 5:19 PM, schrieb Ralf Grosse-Kunstleve:
> without having looked at your code ...
>
> most likely this is a memory issue. run with valgrind (valgrind.org
> <http://valgrind.org> or man valgrind) to pin-point the problem.
>
> On Fri, Jul 20, 2012 at 7:55 AM, Ronny Herzog <herzog at mpi-cbg.de
> <mailto:herzog at mpi-cbg.de>> wrote:
>
>
>     Dear all,
>
>     I want to export a boost::python::dict containing a
>     boost::python::list. However, when I print this list in Python, I
>     get an unlimited output of some strange numbers:
>
>     namespace bp = boost::python;
>
>     class readraw
>     {
>     ....
>
>                      bp::list mk_pyPeak_list()
>                      {
>                              bp::list py_peak_list;
>                              for (int i = 0; i < peak_number; i++)
>                              {
>
>     py_peak_list.append(bp::make___tuple(peak_list[0][i].mz,
>     peak_list[0][i].intensity));
>                              }
>                              return py_peak_list;
>                      }
>
>                      bp::dict peak_list_info()
>                      {
>                              bp::dict info;
>                              //bp::object pn = peak_number;
>                              //info["peakNumber"] = peak_number;
>                              //std::cout <<
>     bp::extract<int>(mk_pyPeak___list().attr("__len__")();
>                              bp::list l(mk_pyPeak_list());
>                              info["peakList"] = l;
>
>                              return info;
>                      }
>              };
>
>     BOOST_PYTHON_MODULE(readraw)
>     {
>              bp::class_<readraw>("readraw", bp::init<int>())
>                      .def("add_peak", &readraw::add_peak)
>                      .def("peak_list_info", &readraw::peak_list_info)
>                      .def("average_scans", &readraw::average_scans)
>                      ;
>
>     In Python:
>      >>> print rawfilereader.peak_list_info()
>
>     Results in smth. like:
>     ...
>     (-431602080.0 <tel:%28-431602080.0>, -6.2774385622041925e+66),
>     (-431602080.0 <tel:%28-431602080.0>, -6.2774385622041925e+66
>     ), (-431602080.0 <tel:%28-431602080.0>, -6.2774385622041925e+66),
>     (-431602080.0 <tel:%28-431602080.0>, -6.2774385622041925e+
>     66), (-431602080.0 <tel:%28-431602080.0>, -6.2774385622041925e+66),
>     (-431602080.0 <tel:%28-431602080.0>, -6.2774385622041925
>     e+66), (-431602080.0 <tel:%28-431602080.0>,
>     -6.2774385622041925e+66), (-431602080.0 <tel:%28-431602080.0>,
>     -6.27743856220419
>     25e+66), (-431602080.0 <tel:%28-431602080.0>,
>     -6.2774385622041925e+66), (-431602080.0 <tel:%28-431602080.0>,
>     -6.277438562204
>     1925e+66), (-431602080.0 <tel:%28-431602080.0>,
>     -6.2774385622041925e+66), (-431602080.0 <tel:%28-431602080.0>,
>     -6.2774385622
>     041925e+66), (-431602080.0 <tel:%28-431602080.0>,
>     -6.2774385622041925e+66), (-431602080.0 <tel:%28-431602080.0>,
>     -6.27743856
>     ...
>
>     What am I doing wrong?
>
>     Thanks for the help,
>     Ronny
>
>     _________________________________________________
>     Cplusplus-sig mailing list
>     Cplusplus-sig at python.org <mailto:Cplusplus-sig at python.org>
>     http://mail.python.org/__mailman/listinfo/cplusplus-sig
>     <http://mail.python.org/mailman/listinfo/cplusplus-sig>
>
>
>
>
> _______________________________________________
> Cplusplus-sig mailing list
> Cplusplus-sig at python.org
> http://mail.python.org/mailman/listinfo/cplusplus-sig
>



From s_sourceforge at nedprod.com  Sat Jul 21 11:40:59 2012
From: s_sourceforge at nedprod.com (Niall Douglas)
Date: Sat, 21 Jul 2012 10:40:59 +0100
Subject: [C++-sig] exporting a boost::python::dict containing a
	boost::python::list
In-Reply-To: <judsic$9cp$1@dough.gmane.org>
References: <jubrh8$ksc$1@dough.gmane.org>,
	<CADfjg2pRftch=0sKE6Q_vNwirV+a3joUXSo+VP0=SeL78Z-3rg@mail.gmail.com>,
	<judsic$9cp$1@dough.gmane.org>
Message-ID: <500A792B.25177.2FC03E4@s_sourceforge.nedprod.com>

On windows, the only near equivalent to valgrind is Intel's suite of 
very expensive tools. If your company already has a licence, they are 
very good. If not, fire up a copy of Linux on your nearest VM node 
and port a small example of the problem in your BPL app over to GCC.

Niall


On 21 Jul 2012 at 11:25, Ronny Herzog wrote:

> Thanks for the answer, but I should add that I am using Windows 7 32Bit 
> with Python 2.6.
> 
> Ronny
> 
> Am 7/20/2012 5:19 PM, schrieb Ralf Grosse-Kunstleve:
> > without having looked at your code ...
> >
> > most likely this is a memory issue. run with valgrind (valgrind.org
> > <http://valgrind.org> or man valgrind) to pin-point the problem.
> >
> > On Fri, Jul 20, 2012 at 7:55 AM, Ronny Herzog <herzog at mpi-cbg.de
> > <mailto:herzog at mpi-cbg.de>> wrote:
> >
> >
> >     Dear all,
> >
> >     I want to export a boost::python::dict containing a
> >     boost::python::list. However, when I print this list in Python, I
> >     get an unlimited output of some strange numbers:
> >
> >     namespace bp = boost::python;
> >
> >     class readraw
> >     {
> >     ....
> >
> >                      bp::list mk_pyPeak_list()
> >                      {
> >                              bp::list py_peak_list;
> >                              for (int i = 0; i < peak_number; i++)
> >                              {
> >
> >     py_peak_list.append(bp::make___tuple(peak_list[0][i].mz,
> >     peak_list[0][i].intensity));
> >                              }
> >                              return py_peak_list;
> >                      }
> >
> >                      bp::dict peak_list_info()
> >                      {
> >                              bp::dict info;
> >                              //bp::object pn = peak_number;
> >                              //info["peakNumber"] = peak_number;
> >                              //std::cout <<
> >     bp::extract<int>(mk_pyPeak___list().attr("__len__")();
> >                              bp::list l(mk_pyPeak_list());
> >                              info["peakList"] = l;
> >
> >                              return info;
> >                      }
> >              };
> >
> >     BOOST_PYTHON_MODULE(readraw)
> >     {
> >              bp::class_<readraw>("readraw", bp::init<int>())
> >                      .def("add_peak", &readraw::add_peak)
> >                      .def("peak_list_info", &readraw::peak_list_info)
> >                      .def("average_scans", &readraw::average_scans)
> >                      ;
> >
> >     In Python:
> >      >>> print rawfilereader.peak_list_info()
> >
> >     Results in smth. like:
> >     ...
> >     (-431602080.0 <tel:%28-431602080.0>, -6.2774385622041925e+66),
> >     (-431602080.0 <tel:%28-431602080.0>, -6.2774385622041925e+66
> >     ), (-431602080.0 <tel:%28-431602080.0>, -6.2774385622041925e+66),
> >     (-431602080.0 <tel:%28-431602080.0>, -6.2774385622041925e+
> >     66), (-431602080.0 <tel:%28-431602080.0>, -6.2774385622041925e+66),
> >     (-431602080.0 <tel:%28-431602080.0>, -6.2774385622041925
> >     e+66), (-431602080.0 <tel:%28-431602080.0>,
> >     -6.2774385622041925e+66), (-431602080.0 <tel:%28-431602080.0>,
> >     -6.27743856220419
> >     25e+66), (-431602080.0 <tel:%28-431602080.0>,
> >     -6.2774385622041925e+66), (-431602080.0 <tel:%28-431602080.0>,
> >     -6.277438562204
> >     1925e+66), (-431602080.0 <tel:%28-431602080.0>,
> >     -6.2774385622041925e+66), (-431602080.0 <tel:%28-431602080.0>,
> >     -6.2774385622
> >     041925e+66), (-431602080.0 <tel:%28-431602080.0>,
> >     -6.2774385622041925e+66), (-431602080.0 <tel:%28-431602080.0>,
> >     -6.27743856
> >     ...
> >
> >     What am I doing wrong?
> >
> >     Thanks for the help,
> >     Ronny
> >
> >     _________________________________________________
> >     Cplusplus-sig mailing list
> >     Cplusplus-sig at python.org <mailto:Cplusplus-sig at python.org>
> >     http://mail.python.org/__mailman/listinfo/cplusplus-sig
> >     <http://mail.python.org/mailman/listinfo/cplusplus-sig>
> >
> >
> >
> >
> > _______________________________________________
> > Cplusplus-sig mailing list
> > Cplusplus-sig at python.org
> > http://mail.python.org/mailman/listinfo/cplusplus-sig
> >
> 
> 
> _______________________________________________
> Cplusplus-sig mailing list
> Cplusplus-sig at python.org
> http://mail.python.org/mailman/listinfo/cplusplus-sig


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From wmamrak at gmail.com  Sat Jul 21 17:41:45 2012
From: wmamrak at gmail.com (Wojciech Mamrak)
Date: Sat, 21 Jul 2012 17:41:45 +0200
Subject: [C++-sig] Factory using embedded Python interpreter
Message-ID: <CAMhLx00A=6k+ww3FGhZRRcGPvS4NmTC3wT8gX4Ks+e7ZPs_oSQ@mail.gmail.com>

Hello list,

I am trying to create C++ objects dynamically (some kind of factory)
with use of embedded Python interpreter (i.e. eval).

Naive implementation:
namespace bp = boost::python;
bp::object main_module = ...;
bp::object main_namespace = ...;

bp::object bpo_ob = bp::eval((type+"()").c_str(), main_namespace);
Object* ob = bp::extract<Object*>(pbo_ob);

Simple eval returns bp::object, so after it goes out of scope PyDECREF
is called and finally Python's garbage collector wipes Object out.

Based on FAQ's entry:
http://www.boost.org/doc/libs/1_50_0/libs/python/doc/v2/faq.html#ownership

I set held_type to std::auto_ptr in Object definition:

BOOST_PYTHON_MODULE(MyModule) {
    class_<Object, std::auto_ptr<Object>>("Object", init<>());
}


but I am not sure how to take the ownership over objects created this
way. I was thinking about:

bp::object bpo_ob = bp::eval((type+"()").c_str(), main_namespace);
std::auto_ptr<Object> ob = bp::extract<std::auto_ptr<Object>>(bpo_ob);
Object* o = ob.release();

but I am not sure about its correctness with respect to memory leaks.
When run, the program does not crash.

Thanks!

From innosam at gmail.com  Sun Jul 22 10:20:58 2012
From: innosam at gmail.com (Harkirat Singh)
Date: Sun, 22 Jul 2012 13:50:58 +0530
Subject: [C++-sig] Boost Python support Python Version.
Message-ID: <CAM7XhrK5NkHoCLF-CTk+9GVM6bmZHg5sC4nm=edH=VK83Pef=w@mail.gmail.com>

Hi all
I will be extending custom libraries to python.
My target system uses python2.4.4.
I have even tried swig, but it seems there isnt full support for python2.4.
It uses some python c++ API not supported in
python2.4.4.

What is the status of boost python regarding this.

Thanks
Sam
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From nat at lindenlab.com  Mon Jul 23 15:06:41 2012
From: nat at lindenlab.com (Nat Goodspeed)
Date: Mon, 23 Jul 2012 09:06:41 -0400
Subject: [C++-sig] Boost Python support Python Version.
In-Reply-To: <CAM7XhrK5NkHoCLF-CTk+9GVM6bmZHg5sC4nm=edH=VK83Pef=w@mail.gmail.com>
References: <CAM7XhrK5NkHoCLF-CTk+9GVM6bmZHg5sC4nm=edH=VK83Pef=w@mail.gmail.com>
Message-ID: <B0F74050-7AA0-4B77-A0A2-AE21F67C9A9E@lindenlab.com>

On Jul 22, 2012, at 4:20 AM, Harkirat Singh <innosam at gmail.com> wrote:

> My target system uses python2.4.4.
> I have even tried swig, but it seems there isnt full support for python2.4. It uses some python c++ API not supported in 
> python2.4.4.

My advice would be to update your Python version. Quite aside from the mere age of Python 2.4, many useful features have been added to the language since then - perhaps most notably in Python 2.5. But why not use 2.7?

From j.reid at mail.cryst.bbk.ac.uk  Wed Jul 25 10:03:56 2012
From: j.reid at mail.cryst.bbk.ac.uk (John Reid)
Date: Wed, 25 Jul 2012 09:03:56 +0100
Subject: [C++-sig] Indexing suite v2 multiple module problem
Message-ID: <juo99c$1vb$1@dough.gmane.org>

Hi,

I'm using a version of the indexing suite I believe I copied from
Roman's codebase some time ago. I've recently refactored my project into
multiple modules and now I'm have some runtime errors when iterating
over sequences in python. At runtime I get the cryptic message:

RuntimeError: get

It is proving a little difficult to track down as it only happens on my
server not on my development machine although it is reproducible every
time. Not all std::vectors that are exposed trigger the error. If I
change the order that my C++ modules are imported then the std::vector
that triggers the error changes.

I'm building a debug python on my server to try to investigate further
but meanwhile I wonder if anyone had any suggestions or had seen this
sort of thing before?

Also where is the latest version of the indexing suite v2 code that I
could use?

Thanks,
John.


From roman.yakovenko at gmail.com  Wed Jul 25 10:44:08 2012
From: roman.yakovenko at gmail.com (Roman Yakovenko)
Date: Wed, 25 Jul 2012 11:44:08 +0300
Subject: [C++-sig] Indexing suite v2 multiple module problem
In-Reply-To: <juo99c$1vb$1@dough.gmane.org>
References: <juo99c$1vb$1@dough.gmane.org>
Message-ID: <CABYYnMzT2qR-Sft+s-nRGpC_K_DEhnvHOCGd35mSYu1428-3dQ@mail.gmail.com>

On Wed, Jul 25, 2012 at 11:03 AM, John Reid <j.reid at mail.cryst.bbk.ac.uk> wrote:
> Hi,
>
> I'm using a version of the indexing suite I believe I copied from
> Roman's codebase some time ago. I've recently refactored my project into
> multiple modules and now I'm have some runtime errors when iterating
> over sequences in python. At runtime I get the cryptic message:
>
> RuntimeError: get
>
> It is proving a little difficult to track down as it only happens on my
> server not on my development machine although it is reproducible every
> time. Not all std::vectors that are exposed trigger the error. If I
> change the order that my C++ modules are imported then the std::vector
> that triggers the error changes.
>
> I'm building a debug python on my server to try to investigate further
> but meanwhile I wonder if anyone had any suggestions or had seen this
> sort of thing before?
>
> Also where is the latest version of the indexing suite v2 code that I
> could use?

Do you use dlopen?

import sys
sys.setdlopenflags(RTLD_NOW | RTLD_GLOBAL)

In multi-module environment you have to share boost python registry.

I would start with this. You can google for "boost python dlopen" and
find a lot of information about the subject.

If I remember right, Py++ contains (generates) some code that queries
the registry and registers the class conditionally.

HTH,
Roman

From j.reid at mail.cryst.bbk.ac.uk  Wed Jul 25 11:34:52 2012
From: j.reid at mail.cryst.bbk.ac.uk (John Reid)
Date: Wed, 25 Jul 2012 10:34:52 +0100
Subject: [C++-sig] Indexing suite v2 multiple module problem
In-Reply-To: <CABYYnMzT2qR-Sft+s-nRGpC_K_DEhnvHOCGd35mSYu1428-3dQ@mail.gmail.com>
References: <juo99c$1vb$1@dough.gmane.org>
	<CABYYnMzT2qR-Sft+s-nRGpC_K_DEhnvHOCGd35mSYu1428-3dQ@mail.gmail.com>
Message-ID: <juoejs$d3c$1@dough.gmane.org>



On 25/07/12 09:44, Roman Yakovenko wrote:
> Do you use dlopen?
>
> import sys
> sys.setdlopenflags(RTLD_NOW | RTLD_GLOBAL)
>
> In multi-module environment you have to share boost python registry.

(Sorry if this is a duplicate post, the last one seemed to disappear)

Thanks, your advice fixed it:

#
# Need to set dlopen flags for multi-module boost.python environment
#
import sys, DLFCN
sys.setdlopenflags(DLFCN.RTLD_NOW | DLFCN.RTLD_GLOBAL)


From gr at componic.co.nz  Tue Jul 31 11:14:34 2012
From: gr at componic.co.nz (Glenn Ramsey)
Date: Tue, 31 Jul 2012 21:14:34 +1200
Subject: [C++-sig] How to create a custom exception derived from Exception
Message-ID: <5017A1FA.8050502@componic.co.nz>


Using boost::python how can I create an a custom exception that is derived from 
Python's Exception? The functionality I would like to get by doing this is to 
provide additional methods for the catching code to retrieve information from 
the exception.

I know it is possible to just wrap and throw my own exception class but it seems 
that because it is not derived from Exception then in certain situations I get 
the error "SystemError: 'finally' pops bad exception".

This example [1] shows how to wrap a C++ exception class...

class MyCPPException : public std::exception {...}

using namespace boost::python;
...

PyObject *myCPPExceptionType=0;

void translate(MyCPPException const &e)
{
     PyErr_SetObject(myCPPExceptionType, object(e).ptr());
}


BOOST_PYTHON_MODULE(MyModule)
{
     ...
	
     class_<MyCPPException> myCPPExceptionClass("MyCPPException"...);
     myCPPExceptionClass
         .def("get_extra_info", &MyCPPException::get_extra_info);

     myCPPExceptionType=myCPPExceptionClass.ptr();

     register_exception_translator<MyCPPException>(&translate);
     ...
}

But this is not derived from Exception.

This example [2] shows how to create an exception that is derived from Exception.

PyObject* createExceptionClass(const char* name, PyObject* baseTypeObj = 
PyExc_Exception)
{
     using std::string;
     namespace bp = boost::python;

     string scopeName = bp::extract<string>(bp::scope().attr("__name__"));
     string qualifiedName0 = scopeName + "." + name;
     char* qualifiedName1 = const_cast<char*>(qualifiedName0.c_str());

     PyObject* typeObj = PyErr_NewException(qualifiedName1, baseTypeObj, 0);
     if(!typeObj) bp::throw_error_already_set();
     bp::scope().attr(name) = bp::handle<>(bp::borrowed(typeObj));
     return typeObj;
}

PyObject* myExceptionTypeObj = 0;

void translate(MyCPPException const &e)
{
     PyErr_SetObject(myExceptionTypeObj, object(e).ptr());
}


BOOST_PYTHON_MODULE(MyModule)
{
     register_exception_translator<MyCPPException>(&translateFunc);
     ...
     myExceptionTypeObj = createExceptionClass("MyException");
     ...
}

But this doesn't have any custom methods to get info from the exception.

How can I do both at the same time?

Glenn

[2] <http://stackoverflow.com/questions/9620268/boost-python-custom-exception-class>

[1] <http://stackoverflow.com/questions/2261858/boostpython-export-custom-exception>

From gr at componic.co.nz  Tue Jul 31 12:22:11 2012
From: gr at componic.co.nz (Glenn Ramsey)
Date: Tue, 31 Jul 2012 22:22:11 +1200
Subject: [C++-sig] How to create a custom exception derived from
	Exception
In-Reply-To: <5017A1FA.8050502@componic.co.nz>
References: <5017A1FA.8050502@componic.co.nz>
Message-ID: <5017B1D3.2080602@componic.co.nz>

On 31/07/12 21:14, Glenn Ramsey wrote:
>
> Using boost::python how can I create an a custom exception that is derived from
> Python's Exception? The functionality I would like to get by doing this is to
> provide additional methods for the catching code to retrieve information from
> the exception.
>
> I know it is possible to just wrap and throw my own exception class but it seems
> that because it is not derived from Exception then in certain situations I get
> the error "SystemError: 'finally' pops bad exception".
>
> This example [1] shows how to wrap a C++ exception class...
>
> class MyCPPException : public std::exception {...}
>
> using namespace boost::python;
> ...
>
> PyObject *myCPPExceptionType=0;
>
> void translate(MyCPPException const &e)
> {
>      PyErr_SetObject(myCPPExceptionType, object(e).ptr());
> }
>
>
> BOOST_PYTHON_MODULE(MyModule)
> {
>      ...
>
>      class_<MyCPPException> myCPPExceptionClass("MyCPPException"...);
>      myCPPExceptionClass
>          .def("get_extra_info", &MyCPPException::get_extra_info);
>
>      myCPPExceptionType=myCPPExceptionClass.ptr();
>
>      register_exception_translator<MyCPPException>(&translate);
>      ...
> }
>
> But this is not derived from Exception.
>
> This example [2] shows how to create an exception that is derived from Exception.
>
> PyObject* createExceptionClass(const char* name, PyObject* baseTypeObj =
> PyExc_Exception)
> {
>      using std::string;
>      namespace bp = boost::python;
>
>      string scopeName = bp::extract<string>(bp::scope().attr("__name__"));
>      string qualifiedName0 = scopeName + "." + name;
>      char* qualifiedName1 = const_cast<char*>(qualifiedName0.c_str());
>
>      PyObject* typeObj = PyErr_NewException(qualifiedName1, baseTypeObj, 0);
>      if(!typeObj) bp::throw_error_already_set();
>      bp::scope().attr(name) = bp::handle<>(bp::borrowed(typeObj));
>      return typeObj;
> }
>
> PyObject* myExceptionTypeObj = 0;
>
> void translate(MyCPPException const &e)
> {
>      PyErr_SetObject(myExceptionTypeObj, object(e).ptr());
> }
>
>
> BOOST_PYTHON_MODULE(MyModule)
> {
>      register_exception_translator<MyCPPException>(&translateFunc);
>      ...
>      myExceptionTypeObj = createExceptionClass("MyException");
>      ...
> }
>
> But this doesn't have any custom methods to get info from the exception.
>
> How can I do both at the same time?
>
> Glenn
>
> [2]
> <http://stackoverflow.com/questions/9620268/boost-python-custom-exception-class>
>
> [1]
> <http://stackoverflow.com/questions/2261858/boostpython-export-custom-exception>

Forgot to mention a couple of things that I tried already...

Passing a tuple of PyExc_Exception and my wrapped custom exception to 
PyErr_NewException, for multiple inheritance, caused an error when attempting to 
load the module in Python, something about incompatible types.

Extracting __dict__ from my wrapped custom exception and passing it to 
PyErr_NewException also caused an error when attempting load the module. I don't 
have it in front of me now but it was complaining about wanting dict instead of 
dictproxy.

Glenn

From talljimbo at gmail.com  Tue Jul 31 12:58:07 2012
From: talljimbo at gmail.com (Jim Bosch)
Date: Tue, 31 Jul 2012 19:58:07 +0900
Subject: [C++-sig] How to create a custom exception derived from
	Exception
In-Reply-To: <5017A1FA.8050502@componic.co.nz>
References: <5017A1FA.8050502@componic.co.nz>
Message-ID: <5017BA3F.6060403@gmail.com>

On 07/31/2012 06:14 PM, Glenn Ramsey wrote:
>
> Using boost::python how can I create an a custom exception that is
> derived from Python's Exception? The functionality I would like to get
> by doing this is to provide additional methods for the catching code to
> retrieve information from the exception.
>

The approach I've taken in the past (sorry, don't have an example right 
now) is to raise a true Python exception (from PyErr_NewException), and 
attach your Boost.Python-wrapped C++ exception to it as an instance 
variable.  Then put a __getattr__ in the true Python exception that 
forwards to the Boost.Python object it holds.

I can try to reconstruct more details if needed, but hopefully that's 
enough to get you started.


Jim