Re: naive question about passing in a NULL via Python

Scott Koranda wrote:
> Suppose I have this simple C function declaration:
> 
> void myfunc(char *mystring);
...
> What is the most "elegant", "easy" and "proper SWIG" way to have this
> function wrapped so that in Python I can simply do
> 
>       import mymodule
>       mymodule.myfunc(<something>)
> 
> and have the C code called with mystring == NULL?
> 
> I think it would be "natural" to call in Python
> 
>       mymodule.myfunc(None)

The default string typemap isn't doing everything that
you want. Try the following in your .i file:

  %module module

  %typemap(in) char *
  {
    if ($input == Py_None)
    {
      $1 = NULL;
    }
    else if (PyString_Check($input))
    {
      $1 = PyString_AsString($input);
    }
    else
    {
      SWIG_fail;
    }
  }

  void myfunc(char *mystring);

Then module.myfunc(None) and module.myfunc("string") will
act as you expect.

-Jerry

_______________________________________________
Swig maillist  -  Swig@xxxxxxxxxxxxxxx
http://mailman.cs.uchicago.edu/mailman/listinfo/swig