How to get a char* from a PyObject which points to

问题:

How can I get a char* from a PyObject which points to a string. For example, this is the python script,

Test.Connect("272.22.20.65", 1234)

and this is the C++ code,

static PyObject* Connect(PyObject *self, PyObject *args)
{
    PyObject* pIP;
    PyObject* pPort;

    if (!PyArg_UnpackTuple(args, "Connect", 2, 2, &pIP, &pPort)) 
    {
        return NULL;
    }

    const char* zIP = GetAsString(pIP);
    long iPort      = PyLong_AsLong(pPort);

I want to get that IP address as a char* (GetAsString is a dummy function :D ). Please note that I'm using Python 3.1.

P.S. I don't think this question got the correct answer , since there is no PyStringObject or PyString_AsString in Python 3. Isn't it ?

回答1:

First you encode it, then you retrieve it. Don't forget to decref the temporary.

回答2:

Here is my portable recipe for it, which makes use the default encoding, where that is applicable. It assumes you start with a PyObject*, named o. If you still have your input tuple from the function call, you can skip the first 2 lines.

PyObject* args = Py_BuildValue("(O)", o);
/* Py_DECREF(o); if o is not borrowed */
if (!args) return 0;
const char* s = 0;
if (!PyArg_ParseTuple(args, "s", &s)) {
  Py_DECREF(args);
  return 0;
}

/* s now points to a const char* - use it, delete args when done */

Py_DECREF(args);

PS: I have not tested it, but it should work with older versions of Python as well. There is nothing on it which is version specific.