Thread: [pygccxml-development] Fwd: [pygccxml-commit] string type mismatch between python and C++

SourceForge Headquarters 225 Broadway Suite 1600 San Diego, CA 92101 +1 (858) 422-6466

---------- Forwarded message ----------
From: Roman Yakovenko <rom...@gm...>
Date: Mon, Apr 7, 2008 at 4:31 PM
Subject: Re: [pygccxml-commit] string type mismatch between python and C++
To: Johnson Lu <joh...@op...>

On Mon, Apr 7, 2008 at 9:55 AM, Johnson Lu <joh...@op...> wrote:
 > Hello Mr. Yakovenko:

 Roman is just fine :-)

 >  The compiler I am using is VC 7.1, and we also use the openTop
 >  libraries.
 >
 >  I am wrapping a class that is part of a large multi-platform product,
 >  and in our product we have some fairly convoluted header includes that,
 >  I think, make strings into different types base on the platform being
 >  compiled on. On VC7.1 simple string became unsigned shorts (heaven only
 >  knows).
 >
 >  Here is a simple snippet of that function as generated by PY++:
 >
 >  struct ClassificationOutput_wrapper : ClassificationOutput, bp::wrapper<
 >  ClassificationOutput > {
 >         .
 >         .
 >         .
 >     virtual void setApplicationName( ::ot::String const &
 >  applicationName ) {
 >         if( bp::override func_setApplicationName = this->get_override(
 >  "setApplicationName" ) )
 >             func_setApplicationName( applicationName );
 >         else
 >             this->ClassificationOutput::setApplicationName(
 >  applicationName );
 >     }
 >     void default_setApplicationName( ::ot::String const &
 >  applicationName ) {
 >         ClassificationOutput::setApplicationName( applicationName );
 >     }
 >         .
 >         .
 >         .
 >  }
 >  BOOST_PYTHON_MODULE(pyplusplus){
 >     bp::class_< ClassificationOutput_wrapper, boost::noncopyable >(
 >  "ClassificationOutput" )
 >         .def( bp::init< >() )
 >         .
 >         .
 >         .
 >         .def(
 >             "setApplicationName"
 >             , &::ClassificationOutput::setApplicationName
 >             , &ClassificationOutput_wrapper::default_setApplicationName
 >             , ( bp::arg("applicationName") ) )
 >
 >
 >  And here is the original .h snippet for the function...
 >
 >  class ClassificationBuiltinImplDeclSpec ClassificationOutput : public
 >  IClassificationModifiableOutput
 >  {
 >         .
 >         .
 >         .
 >   virtual void setApplicationName(const String& applicationName) ;
 >
 >  And my test code simply creates a C++ ClassificationOutput object:
 >
 >   ClassificationOutput mm;
 >         mm.setApplicationName(OPTIER_T("monty python"));
 >         mm.setUserName(OPTIER_T("jclu"));
 >         .
 >         .
 >         .
 >                 bpl::object pyCls(boost::ref(mm));
 >                 main_namespace["output"] = pyCls;
 >
 >  Pass it to Python via name space addition to the python dictionary, then
 >  used a simple python code:
 >         output.setApplicationName("anApplication")  # and this line does
 >  not work.
 >         output.getUserName()    # returns jclu, so python can read from
 >  C++
 >
 >  All seem very straight forward, except not quite so, for me.
 >
 >  Again, really appreciate your help.

 Okey, I think I understand the problem and was able to reproduce it.

 Solution:
 1. http://boost.org/doc/libs/1_35_0/libs/python/doc/v2/faq.html#custom_string
 2. http://language-binding.net/pyplusplus/documentation/inserting_code.html#insert-code-to-module

 Explanation: I guess Boost.Python was compiled with "Yes
 (/Zc:wchar_t)" option turned on. Thus class std::basic_string<
 unsigned short > and std::basic_string< wchar_t > are 2 different
 classes. So you will have to define your own string conversion or
 recompile all your source code with the option.

 HTH

 --
 Roman Yakovenko
 C++ Python language binding
 http://www.language-binding.net/

-- 
Roman Yakovenko
C++ Python language binding
http://www.language-binding.net/