Function PyArray_DescrNew

numpy/core/src/multiarray/descriptor.c:1903–1953

NUMPY_API * base cannot be NULL */

 * base cannot be NULL
 */
NPY_NO_EXPORT PyArray_Descr *
PyArray_DescrNew(PyArray_Descr *base)
{
    PyArray_Descr *newdescr = PyObject_New(PyArray_Descr, Py_TYPE(base));

    if (newdescr == NULL) {
        return NULL;
    }
    /* Don't copy PyObject_HEAD part */
    memcpy((char *)newdescr + sizeof(PyObject),
           (char *)base + sizeof(PyObject),
           sizeof(PyArray_Descr) - sizeof(PyObject));

    /*
     * The c_metadata has a by-value ownership model, need to clone it
     * (basically a deep copy, but the auxdata clone function has some
     * flexibility still) so the new PyArray_Descr object owns
     * a copy of the data. Having both 'base' and 'newdescr' point to
     * the same auxdata pointer would cause a double-free of memory.
     */
    if (base->c_metadata != NULL) {
        newdescr->c_metadata = NPY_AUXDATA_CLONE(base->c_metadata);
        if (newdescr->c_metadata == NULL) {
            PyErr_NoMemory();
            /* TODO: This seems wrong, as the old fields get decref'd? */
            Py_DECREF(newdescr);
            return NULL;
        }
    }

    if (newdescr->fields == Py_None) {
        newdescr->fields = NULL;
    }
    Py_XINCREF(newdescr->fields);
    Py_XINCREF(newdescr->names);
    if (newdescr->subarray) {
        newdescr->subarray = PyArray_malloc(sizeof(PyArray_ArrayDescr));
        if (newdescr->subarray == NULL) {
            Py_DECREF(newdescr);
            return (PyArray_Descr *)PyErr_NoMemory();
        }
        memcpy(newdescr->subarray, base->subarray, sizeof(PyArray_ArrayDescr));
        Py_INCREF(newdescr->subarray->shape);
        Py_INCREF(newdescr->subarray->base);
    }
    Py_XINCREF(newdescr->typeobj);
    Py_XINCREF(newdescr->metadata);
    newdescr->hash = -1;

    return newdescr;
}

/*
 * should never be called for builtin-types unless