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pythoncpython-c-apipython-extensionspython-embedding

Create an object using Python's C API


Say I have my object layout defined as:

typedef struct {
    PyObject_HEAD
    // Other stuff...
} pyfoo;

...and my type definition:

static PyTypeObject pyfoo_T = {
    PyObject_HEAD_INIT(NULL)
    // ...

    pyfoo_new,
};

How do I create a new instance of pyfoo somewhere within my C extension?


Solution

  • Call PyObject_New(), followed by PyObject_Init().

    EDIT: The best way is to call the class object, just like in Python itself:

    /* Pass two arguments, a string and an int. */
    PyObject *argList = Py_BuildValue("si", "hello", 42);
    
    /* Call the class object. */
    PyObject *obj = PyObject_CallObject((PyObject *) &pyfoo_T, argList);
    
    /* Release the argument list. */
    Py_DECREF(argList);