Question

Python is calling a C++ function (wrapped using swig).

C++:

  std::wstring getFilePathMultiByte();

I can call this function in python. Question is how do I use this returned wstring? want to append filename to this path which gives error as shown in output below.

Python:

  path = getFilePathMultiByte()
  print path, type(path)
  file = path + "/Information.log"

Output:

_2012ad3900000000_p_std__wstring, type 'SwigPyObject'
TypeError: unsupported operand type(s) for +: 'SwigPyObject' and 'str'

How do I create a std::wstring in python? That may allow concatenation for me.

Thanks.

Answer 1

The following example worked as intended with SWIG 2.0 on my machine:

%module test

%include "std_wstring.i"

%inline %{
  std::wstring foo() {
    return L"hi";
  }
%}

Which I then tested with:

Python 2.7.3rc2 (default, Apr 22 2012, 22:30:17)
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import test
>>> path = test.foo()
>>> print path, type(path)
hi <type 'unicode'>
>>> file = path + "/Information.log"
>>> print file
hi/Information.log
>>>

I’m not exactly sure what you’ve done wrong here – my guess would be you haven’t got %include "std_wstring.i", but it’s hard to say for certain given what you’ve shown.