From stefanrin at gmail.com  Tue Mar  5 15:03:30 2019
From: stefanrin at gmail.com (Stefan Ring)
Date: Tue, 5 Mar 2019 21:03:30 +0100
Subject: [C++-sig] Calling python function repr from C++ using
 boost.python (possible?)
In-Reply-To: <449WC52LTNzndTf@mail.python.org>
References: <449WC52LTNzndTf@mail.python.org>
Message-ID: <CAAxjCEwpsZ157J8N=iySq1hj_qd5m8bEct5VyU0_wC=uyVNCyw@mail.gmail.com>

On Sat, Mar 2, 2019 at 6:12 PM Jones, Torrin A (US)
<torrin.jones at baesystems.com> wrote:
>
> Is it possible to call repr from C++ on a C++ object that can be converted to python?  Let me explain.
>
>
>
> I have an enum that I converted to python using boost::python::enum_().  That class already provides a good repr() to python (thanks to the boost::python developers for that).  However that enum is used as a type on a member in another C++ class that I have where boost::python does not provide a good repr().  So I?m trying to provide one and thought, it sure would be nice if I could just call repr() on the member.  I assume I have to convert the value on that member to python first, some kind of way then call repr?  Is that possible?  Or is there a better way?
>
>
>
> Example:
>
>
>
> Typedef enum
>
> {
>
>    V1 = 0,
>
>    V2 = 5,
>
>    V3 = 6
>
> } values;
>
>
>
> Class ValueExample
>
> {
>
>    Public:
>
>       ValueExample(const values& v) {m_value = v};
>
>       Values getValue() const { return m_value };
>
>    Private:
>
>       Values m_value;
>
> }
>
>
>
> Std::string
>
> ValueExampleRepr(const ValueExample& object)
>
> {
>
>    Std::stringstream ss;
>
>
>
>    // What do I put here?
>
>    // Ss << repr(object.getValue());
>
>
>
>    Return ss::str();
>
> }
>
>
>
> Boost::python::enum_<values> values(?values?);
>
> Values.value(?V1?, V1);
>
> Values.value(?V2?, V2);
>
> Values.value(?V3?, V3);
>
>
>
> Boost::python::class_<ValueExample> ValueExample(?ValueExample?);
>
>
>
> ValueExample(?__repr__?, ValueExampleRepr);

I can only come up with this:

Ss << extract<std::string>(boost::python::object(object.getValue()).attr("__repr__")())();

From torrin.jones at baesystems.com  Sun Mar 10 13:47:38 2019
From: torrin.jones at baesystems.com (Jones, Torrin A (US))
Date: Sun, 10 Mar 2019 17:47:38 +0000
Subject: [C++-sig] Calling python function repr from C++ using
 boost.python (possible?)
In-Reply-To: <CAAxjCEwpsZ157J8N=iySq1hj_qd5m8bEct5VyU0_wC=uyVNCyw@mail.gmail.com>
Message-ID: <44HTHj2r7CzpCdD@mail.python.org>

This worked very well thanks.

-----Original Message-----
From: Stefan Ring [mailto:stefanrin at gmail.com] 
Sent: Tuesday, March 05, 2019 12:04 PM
To: Development of Python/C++ integration <cplusplus-sig at python.org>
Cc: Jones, Torrin A (US) <torrin.jones at baesystems.com>
Subject: Re: [C++-sig] Calling python function repr from C++ using boost.python (possible?)

*** WARNING ***
EXTERNAL EMAIL -- This message originates from outside our organization.


On Sat, Mar 2, 2019 at 6:12 PM Jones, Torrin A (US) <torrin.jones at baesystems.com> wrote:
>
> Is it possible to call repr from C++ on a C++ object that can be converted to python?  Let me explain.
>
>
>
> I have an enum that I converted to python using boost::python::enum_().  That class already provides a good repr() to python (thanks to the boost::python developers for that).  However that enum is used as a type on a member in another C++ class that I have where boost::python does not provide a good repr().  So I?m trying to provide one and thought, it sure would be nice if I could just call repr() on the member.  I assume I have to convert the value on that member to python first, some kind of way then call repr?  Is that possible?  Or is there a better way?
>
>
>
> Example:
>
>
>
> Typedef enum
>
> {
>
>    V1 = 0,
>
>    V2 = 5,
>
>    V3 = 6
>
> } values;
>
>
>
> Class ValueExample
>
> {
>
>    Public:
>
>       ValueExample(const values& v) {m_value = v};
>
>       Values getValue() const { return m_value };
>
>    Private:
>
>       Values m_value;
>
> }
>
>
>
> Std::string
>
> ValueExampleRepr(const ValueExample& object)
>
> {
>
>    Std::stringstream ss;
>
>
>
>    // What do I put here?
>
>    // Ss << repr(object.getValue());
>
>
>
>    Return ss::str();
>
> }
>
>
>
> Boost::python::enum_<values> values(?values?);
>
> Values.value(?V1?, V1);
>
> Values.value(?V2?, V2);
>
> Values.value(?V3?, V3);
>
>
>
> Boost::python::class_<ValueExample> ValueExample(?ValueExample?);
>
>
>
> ValueExample(?__repr__?, ValueExampleRepr);

I can only come up with this:

Ss << extract<std::string>(boost::python::object(object.getValue()).attr("__repr__")())();

From schmmark at ethz.ch  Mon Mar 18 11:07:15 2019
From: schmmark at ethz.ch (Markus Johann Schmidt)
Date: Mon, 18 Mar 2019 16:07:15 +0100
Subject: [C++-sig] Fail to build Boost Python Tutorial: LNK1120: 55
 unresolved externals
Message-ID: <e96c4ff6-0891-9a91-ddef-032dbeb2d04f@ethz.ch>

Dear all,


I try to learn boost and in particular the Python extension part. But I
am already failing with building the tutorial. I am quite a beginner
with compiling in C++

I use a Win10 64bit System. I have to use VS2015, because for a
proprietary library I have to compile later in msvc120 (64bit). VS2017
is installed on the computer as well.


I tried to following for compilation


 1. ?Launch the "Developer Command Prompt for VS2015"
 2. Setting Python environment:
    "C:\Users\schmmark\Anaconda3\Scripts\activate.bat"
    "C:\Users\schmmark\Anaconda3\envs\py36"
 3. cd C:\Users\schmmark\Downloads\boost_1_69_0\boost_1_69_0
 4. bootstrap.bat (successful)
 5. b2.exe toolset=msvc-14.0 address-model=64 (successful)
 6. cd libs\python\example\tutorial
 7. ..\..\..\..\bjam.exe toolset=msvc-14.0 address-model=64
    --debug-configuration


I modified the Jamfile from tutorial folder and Jamroot from example
folder as can be found in the attachment. I get the error `hello_ext.pyd
: fatal error LNK1120: 55 unresolved externals`
?A complete output of my command prompt is attached as well.

May my problem be

  * wrong import of python library? I try to use a wildcard in lib
    boost_python instead of `boost_python36-vc140-mt-x64-1_69` But the
    error stays the same when I rename it
  * Some issues with 32bit and 64bit detection?
  * Am I missing some imports?


Thanks in advance for your support
Markus
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From stefanrin at gmail.com  Tue Mar 19 12:20:03 2019
From: stefanrin at gmail.com (Stefan Ring)
Date: Tue, 19 Mar 2019 17:20:03 +0100
Subject: [C++-sig] Fail to build Boost Python Tutorial: LNK1120: 55
 unresolved externals
In-Reply-To: <e96c4ff6-0891-9a91-ddef-032dbeb2d04f@ethz.ch>
References: <e96c4ff6-0891-9a91-ddef-032dbeb2d04f@ethz.ch>
Message-ID: <CAAxjCEz3TX93iFHgcGf2KtaHgQLmidKe-S9MPYw5+8w=kHQL9Q@mail.gmail.com>

On Tue, Mar 19, 2019 at 3:52 PM Markus Johann Schmidt <schmmark at ethz.ch> wrote:
>  A complete output of my command prompt is attached as well.
>
> May my problem be
>
> wrong import of python library? I try to use a wildcard in lib boost_python instead of `boost_python36-vc140-mt-x64-1_69` But the error stays the same when I rename it
> Some issues with 32bit and 64bit detection?
> Am I missing some imports?

Looks like issues with MSVC's runtime libraries. Maybe rename the
other Visual Studio version's installation directories temporarily to
avoid wrong versions being picked up? I have not tried following the
tutorial myself, though. Have not used Boost on Windows in a decade.

From virali.vora2010 at gmail.com  Thu Mar 21 15:04:04 2019
From: virali.vora2010 at gmail.com (virali vora)
Date: Fri, 22 Mar 2019 00:34:04 +0530
Subject: [C++-sig] GSOC
Message-ID: <CAJyctW4uyrS8B5M3=d7WFT7zVT4+=vB+LvMyDitnNN1y5fpyvA@mail.gmail.com>

Hi,
I went through the project details of Boost Python-C++ integeration and
found them quite interesting.
I would like to contribute to the project.
The project says that we need to implement a c++ interface for Python' set
type.
So, should that include all the set methods of Python?
Also, is there any discussion channel where I can communicate with you?

Thanks.
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From schmidt at ifd.mavt.ethz.ch  Wed Mar 20 08:19:33 2019
From: schmidt at ifd.mavt.ethz.ch (Schmidt  Markus Johann)
Date: Wed, 20 Mar 2019 12:19:33 +0000
Subject: [C++-sig] Fail to build Boost Python Tutorial: LNK1120: 55
 unresolved externals
In-Reply-To: <CAAxjCEz3TX93iFHgcGf2KtaHgQLmidKe-S9MPYw5+8w=kHQL9Q@mail.gmail.com>
References: <e96c4ff6-0891-9a91-ddef-032dbeb2d04f@ethz.ch>,
 <CAAxjCEz3TX93iFHgcGf2KtaHgQLmidKe-S9MPYw5+8w=kHQL9Q@mail.gmail.com>
Message-ID: <e491cafaf3ea48938ba8e1bab4093fbe@ifd.mavt.ethz.ch>

Dear Stefan,


might indeed be the case. Now I compiled the sources again with the VS2017 command prompt. When I then try to compile the tutorial, I get the strange output


C:\Users\schmmark\user-config.jam:3: Unescaped special character in argument 'C:Program
notice: [msvc-cfg] msvc-14.0 detected, command: 'C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\bin\cl.exe'
notice: [msvc-cfg] msvc-12.0 detected, command: 'C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\bin\cl.exe'
notice: [msvc-cfg] msvc-11.0 detected, command: 'C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\bin\cl.exe'
notice: [msvc-cfg] msvc-14.1 detected, command: 'C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\VC\Tools\MSVC\14.16.27023\bin\Hostx64\x64\cl.exe'
notice: will use 'C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\bin\cl.exe' ''C:Program' 'Files' '(x86)Microsoft' 'Visual' 'Studio' '12.0VCbincl.exe'' for msvc, condition <toolset>msvc-12.0

[...]

notice: Loading project-config configuration file 'project-config.jam' from '../../../..'.
notice: will use 'C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\VC\Tools\MSVC\14.16.27023\bin\Hostx64\x64\cl.exe' for msvc, condition <toolset>msvc-14.1

And finally
LINK : fatal error LNK1181: cannot open input file 'boost_python36-vc141-mt-x64-1_69.lib'


When I change the entry in the project-config.jam to `msvc : 12.0`  the notice of using msvc-14.1 vanishes, but the LNK error still comes up.


________________________________
From: Stefan Ring <stefanrin at gmail.com>
Sent: 19 March 2019 17:20:03
To: Development of Python/C++ integration
Cc: Schmidt Markus Johann
Subject: Re: [C++-sig] Fail to build Boost Python Tutorial: LNK1120: 55 unresolved externals

On Tue, Mar 19, 2019 at 3:52 PM Markus Johann Schmidt <schmmark at ethz.ch> wrote:
>  A complete output of my command prompt is attached as well.
>
> May my problem be
>
> wrong import of python library? I try to use a wildcard in lib boost_python instead of `boost_python36-vc140-mt-x64-1_69` But the error stays the same when I rename it
> Some issues with 32bit and 64bit detection?
> Am I missing some imports?

Looks like issues with MSVC's runtime libraries. Maybe rename the
other Visual Studio version's installation directories temporarily to
avoid wrong versions being picked up? I have not tried following the
tutorial myself, though. Have not used Boost on Windows in a decade.
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From stefan at seefeld.name  Thu Mar 21 15:13:16 2019
From: stefan at seefeld.name (stefan)
Date: Thu, 21 Mar 2019 15:13:16 -0400
Subject: [C++-sig] GSOC
In-Reply-To: <CAJyctW4uyrS8B5M3=d7WFT7zVT4+=vB+LvMyDitnNN1y5fpyvA@mail.gmail.com>
References: <CAJyctW4uyrS8B5M3=d7WFT7zVT4+=vB+LvMyDitnNN1y5fpyvA@mail.gmail.com>
Message-ID: <7e696f5d-86b8-9140-8757-aa27707f836d@seefeld.name>

Hi Virali,

On 2019-03-21 3:04 p.m., virali vora wrote:
> Hi,
> I went through the project details of Boost Python-C++ integeration 
> and found them quite interesting.
> I would like to contribute to the project.
> The project says that we need to implement a c++ interface for Python' 
> set type.
> So, should that include all the set methods of Python?

Yes.

> Also, is there any discussion channel where I can communicate with you?

I'd suggest https://gitter.im/boostorg/python

Stefan

--

       ...ich hab' noch einen Koffer in Berlin...
     

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From sarah.rust at roosterteeth.com  Mon Mar 25 10:38:09 2019
From: sarah.rust at roosterteeth.com (Sarah Rust)
Date: Mon, 25 Mar 2019 09:38:09 -0500
Subject: [C++-sig] Linking issues with Boost.Python 1.69.0, Python 2.7,
 MSVC 14.0
Message-ID: <CAAd5Bi8D5Cy0ype3hTv81++oEdvxnhetiGkTUJQC9KZCZhYdhg@mail.gmail.com>

Hello!

I have been trying to build and link the latest Boost.Python to work with
Python 2.7 and my Visual Studio 2015 project (MSVC 14.0) with x64
configuration. I've added the Boost library and Boost include directory to
my project's properties, but I am getting the following error when I create
a BOOST_PYTHON_MODULE:

error LNK2001: unresolved external symbol "__declspec(dllimport) struct
_object * __cdecl boost::python::detail::init_module(char const *,void
(__cdecl*)(void))" (__imp_?init_module at detail@python at boost@@YAPEAU_object@
@PEBDP6AXXZ at Z)

Please let me know how others are doing this.

Thanks,
Sarah
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From stefanrin at gmail.com  Wed Mar 27 05:09:41 2019
From: stefanrin at gmail.com (Stefan Ring)
Date: Wed, 27 Mar 2019 10:09:41 +0100
Subject: [C++-sig] Linking issues with Boost.Python 1.69.0, Python 2.7,
 MSVC 14.0
In-Reply-To: <CAAd5Bi8D5Cy0ype3hTv81++oEdvxnhetiGkTUJQC9KZCZhYdhg@mail.gmail.com>
References: <CAAd5Bi8D5Cy0ype3hTv81++oEdvxnhetiGkTUJQC9KZCZhYdhg@mail.gmail.com>
Message-ID: <CAAxjCEz1EXkMikT46VP=x3xMK5TO_b85gLLoYrPY80v8YCH0Gw@mail.gmail.com>

On Tue, Mar 26, 2019 at 3:27 PM Sarah Rust <sarah.rust at roosterteeth.com> wrote:
>
> Hello!
>
> I have been trying to build and link the latest Boost.Python to work with Python 2.7 and my Visual Studio 2015 project (MSVC 14.0) with x64 configuration. I've added the Boost library and Boost include directory to my project's properties, but I am getting the following error when I create a BOOST_PYTHON_MODULE:
>
> error LNK2001: unresolved external symbol "__declspec(dllimport) struct _object * __cdecl boost::python::detail::init_module(char const *,void (__cdecl*)(void))" (__imp_?init_module at detail@python at boost@@YAPEAU_object@@PEBDP6AXXZ at Z)

Have you built Python yourself? With which compiler? Are you linking
against its import lib (for DLL use at run time)? Could you maybe use
the static version of Boost?

Actually while writing this, a though came up: Are you even linking
against the Boost Python library?

> Please let me know how others are doing this.

Probably not at all ;).

From pavol.juhas at gmail.com  Tue Mar 26 14:34:57 2019
From: pavol.juhas at gmail.com (Pavol Juhas)
Date: Tue, 26 Mar 2019 14:34:57 -0400
Subject: [C++-sig] argument conversion of numpy.int64 to double
Message-ID: <CAA44gkV+WNWtycvvjVxwfb-rJ-bT3jrimv_bvACAe+FBe5M4-Q@mail.gmail.com>

Hello,

After wrapping a simple C++ function of a double argument with
boost python, I have noticed it crashes when called from Python
with a numpy.int64 value.  This is a likely situation, for example when
evaluated for values from numpy.arange.
Please see below for a minimum example.

Is there some simple way of telling the wrapper how to handle
numpy.int64 arguments?

BTW, I have noticed that the boost/numpy library sets up several scalar
converters on its initialization - this happens in boost/python/numpy.hpp
<https://github.com/boostorg/python/blob/6f72675bff276599ffdccb9681018d8b2e367bc2/include/boost/python/numpy.hpp>
 and
then in the register_scalar_converters
<https://github.com/boostorg/python/blob/6f72675bff276599ffdccb9681018d8b2e367bc2/src/numpy/dtype.cpp>
function.
However, adding a
call to boost::python::numpy::initialize did not make a difference
in my example.

Thank you for any advice.  Best,

Pavol

// dbfunction.cpp
------------------------------------------------------------

#include <boost/python/module.hpp>
#include <boost/python/def.hpp>
#include <boost/python/numpy.hpp>

double duplicate(double x)
{
    return 2 * x;
}

BOOST_PYTHON_MODULE(dbfunction)
{
    using boost::python::def;
    // no difference with line below
    // boost::python::numpy::initialize();
    def("duplicate", duplicate);
}

//
---------------------------------------------------------------------------

# TEST

$ python -c 'import dbfunction, numpy;
dbfunction.duplicate(numpy.int64(0))'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
Boost.Python.ArgumentError: Python argument types in
    dbfunction.duplicate(numpy.int64)
did not match C++ signature:
    duplicate(double)
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From damika97.10 at gmail.com  Wed Mar 27 13:11:22 2019
From: damika97.10 at gmail.com (Damika Gamlath)
Date: Wed, 27 Mar 2019 22:41:22 +0530
Subject: [C++-sig] GSOC 2019 Boost.Python
Message-ID: <CACmu=Z_6=NNhWk4TJTW+O9a0pwabcgd-z6ecYaJYcQNG5SGZdw@mail.gmail.com>

Hi, I am Damika Gamlath an undergraduate from Department of Computer
Science & Engineering, University of Moratuwa, Sri Lanka.

I am interested to participate in GSOC 2019. I would like to know about
project ideas under Boost.Python. Further I would like to be guided about
next steps.

Thank you!

Best regards,
Damika Gamlath
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