Function PyArray_SetField

numpy/core/src/multiarray/methods.c:467–500

NUMPY_API Set a subset of bytes from each element of the array steals reference to dtype, must not be NULL */

  steals reference to dtype, must not be NULL
*/
NPY_NO_EXPORT int
PyArray_SetField(PyArrayObject *self, PyArray_Descr *dtype,
                 int offset, PyObject *val)
{
    PyObject *ret = NULL;
    int retval = 0;

    if (self == NULL) {
        PyErr_SetString(PyExc_ValueError,
            "self is NULL in PyArray_SetField");
        return -1;
    }

    if (dtype == NULL) {
        PyErr_SetString(PyExc_ValueError,
            "dtype is NULL in PyArray_SetField");
        return -1;
    }

    if (PyArray_FailUnlessWriteable(self, "assignment destination") < 0) {
        Py_DECREF(dtype);
        return -1;
    }

    /* getfield returns a view we can write to */
    ret = PyArray_GetField(self, dtype, offset);
    if (ret == NULL) {
        return -1;
    }

    retval = PyArray_CopyObject((PyArrayObject *)ret, val);
    Py_DECREF(ret);
    return retval;
}

static PyObject *
array_setfield(PyArrayObject *self, PyObject *args, PyObject *kwds)