Re: [C++-sig] How to get output from python embedded in VC++

Hi Imre,


I tried to use boost.python as you advised. Build boost.python with 


But I got a error in the import.hpp as below:
------------------------import.hpp start ----------------------------------------
namespace boost 
{ 
namespace python 
{


object BOOST_PYTHON_DECL import(str name)
{
  // should be 'char const *' but older python versions don't use 'const' yet.
  char *n = python::extract<char *>(name);
  python::handle<> module(PyImport_ImportModule(n));   <---here is where the error raised. n is "__main__"
  return python::object(module);
}


}  // namespace boost::python
}  // namespace boost
------------------------import.hpp end----------------------------------------


I copied your code and just replaced 'script.py' with the name of my own file. I found the error raised when the code importing module "__main__". 


That's my first time to use boost.python. Could you help about this issue?


Thanks a lot.
Best Regards,


John.





At 2017-07-21 23:13:37, "Horváth Imre István" <imre...@gmail.com> wrote:
>Hi John!>>If you want to embed python in c++ app and exchange data between c++ and>python, take a look at the boost::python library.>It's also a platform independent solution (my app's target platforms are>windows vs2015 and linux CentOS7).>>You can do something like this:>>    using namespace boost::python;>    Py_Initialize();>    try {>        boost::python::object main_module =>boost::python::import("__main__");>        boost::python::object main_namespace =>main_module.attr("__dict__");>>        boost::python::dict mydata;>        mydata["x"] = 5;>        mydata["foo"] = boost::python::dict();>        mydata["foo"]["bar1"] = "data1";>        mydata["foo"]["bar2"] = "data2";>>        // you can declare variables in the python namespace from c++>        main_namespace["mydata"] = mydata;>>        // in the script there is a mydata variable: {'x': 5, 'foo':>{'bar1': 'data1', 'bar2': 'data2'}}>        boost::python::object ignored = exec_file("script.py",>main_namespace, main_namespace);>        >        // declare a variable named return_value in the script, >        // and you can extract it's value to c++ like this>        std::wstring output =>extract<std::wstring>(main_namespace["return_value"]);>>    } catch( boost::python::error_already_set) {>        PyErr_Print();>    }>>(If your python script has some output, don't forget to redirect boost>std::cout etc)>>Best regards:>Imre>>>2017. 07. 20, csütörtök keltezéssel 11.25-kor Jian ezt írta:>> Dear Gurus,>> >> I want to embed python interpreter in my program. What I want is to>> redirect those output to a control such as RICHEDIT which can be>> modified as a output window in my program. So I can write *.py files>> outside of program and invoke it inside program as a script file. In>> order to get information output by the *.py file I need to get the>> stdin&stdout. I have tried some workflow but not perfect.>> >> 1). I have tried use Allocconsle(). But I can only get the output info>> printed by std::out & printf() in the current code. all things which>> are printed by python35.dll are missing. I used print('xxxx') in the>> *.py file to test the output. Those *.py files are OK in command line>> mode.>> >> 2). I also tried to derive class basic_streambuf and overwrite the>> in/out functions. It works only for output from std::out. Text from>> printf() as well as from dlls are missing.>> >> 3). then I tried to use linker settings as below. >> >> #pragma comment( linker,>> "/subsystem:console /entry:wWinMainCRTStartup" )>> >> A cmd window is created along with the program. everything output from>> current process and dlls are retrieved successfully as I want. But the>> cmd window is not easy to control.>> >> Is there a better way for this purpose? >> >> Thanks in advance for your kind help.>> >> Best Regards,>> >> John. >> >> >> >> >>  >> >> _______________________________________________>> Cplusplus-sig mailing list>> Cplu...@python.org>> https://mail.python.org/mailman/listinfo/cplusplus-sig>>>_______________________________________________>Cplusplus-sig mailing list>Cplu...@python.org>https://mail.python.org/mailman/listinfo/cplusplus-sig