Function PyArray_CheckAxis

numpy/core/src/multiarray/ctors.c:2795–2842

NUMPY_API * PyArray_CheckAxis * * check that axis is valid * convert 0-d arrays to 1-d arrays */

 * convert 0-d arrays to 1-d arrays
 */
NPY_NO_EXPORT PyObject *
PyArray_CheckAxis(PyArrayObject *arr, int *axis, int flags)
{
    PyObject *temp1, *temp2;
    int n = PyArray_NDIM(arr);

    if (*axis == NPY_MAXDIMS || n == 0) {
        if (n != 1) {
            temp1 = PyArray_Ravel(arr,0);
            if (temp1 == NULL) {
                *axis = 0;
                return NULL;
            }
            if (*axis == NPY_MAXDIMS) {
                *axis = PyArray_NDIM((PyArrayObject *)temp1)-1;
            }
        }
        else {
            temp1 = (PyObject *)arr;
            Py_INCREF(temp1);
            *axis = 0;
        }
        if (!flags && *axis == 0) {
            return temp1;
        }
    }
    else {
        temp1 = (PyObject *)arr;
        Py_INCREF(temp1);
    }
    if (flags) {
        temp2 = PyArray_CheckFromAny((PyObject *)temp1, NULL,
                                     0, 0, flags, NULL);
        Py_DECREF(temp1);
        if (temp2 == NULL) {
            return NULL;
        }
    }
    else {
        temp2 = (PyObject *)temp1;
    }
    n = PyArray_NDIM((PyArrayObject *)temp2);
    if (check_and_adjust_axis(axis, n) < 0) {
        Py_DECREF(temp2);
        return NULL;
    }
    return temp2;
}

/*NUMPY_API
 * Zeros