#include "numpy/arrayobject.h"
#include "numpy/ndarraytypes.h"

// obj is your PyArrayObject*
PyArray_Descr* descr = PyArray_DESCR((PyArrayObject*)obj);

// Make sure it's a datetime or timedelta type
if (descr->type_num == NPY_DATETIME || descr->type_num == NPY_TIMEDELTA) {
    PyArray_DatetimeMetaData* meta = (PyArray_DatetimeMetaData*)descr->c_metadata;

    if (meta != NULL) {
        NPY_DATETIMEUNIT unit = meta->base;

        // Now unit is an enum value like NPY_FR_D, NPY_FR_M, etc.
        // You can switch on `unit` or print it
    }
}