Help with tuples please?

[Fredrik Lundh]

Arinte <shouldbe at message.com> wrote:
> Here is were my PyArg_ParseTuple is failing...
> 
> in python's source getargs.c
> 
>  if (!PyTuple_Check(args))
> 
>   PyErr_SetString(PyExc_SystemError,
>       "new style getargs format but argument is not a tuple");
> 
> I don't understand why that is happening?  Is there another way to get the
> value from a PyObject
> 
> This is my c++ code...
> 
>   char* vstr;
>   nobj = PyObject_GetAttrString(tobj,"argname"); <-successful, nobj not null
>   if(!PyArg_ParseTuple(nobj, "s", &vstr)){         <-here is where it fails
>    appcallback()->messageBox("not again");
>   }
> 
> tobj is an object of the type below from an array (list) that I pass from
> python to c++.
> 
> class PossArg:
>  argname=""

argname sure looks like a string to me.

the parsetuple function is used to pull tuples apart, mostly
when dealing with argument tuples.  but a string is not a
tuple.

to deal with string objects, use the PyString functions:
http://www.python.org/doc/current/api/stringObjects.html

typical usage patterns:

    char *p;
    int n;

    if (PyString_Check(nobj)) {
        p = PyString_AS_STRING(nobj);
        n = PyString_GET_SIZE(nobj);
        ... /* use as byte buffer */
    }

or:

    if ((p = PyString_AsString(nobj)) != NULL)
        ... /* use as null terminated C string */

</F>