Function count_boolean_trues

numpy/core/src/multiarray/item_selection.c:2635–2639

 * Returns -1 on error.
 */
NPY_NO_EXPORT NPY_GCC_OPT_3 npy_intp
count_boolean_trues(int ndim, char *data, npy_intp const *ashape, npy_intp const *astrides)
{
    return count_nonzero_int(ndim, data, ashape, astrides, 1);
}

/*NUMPY_API
 * Counts the number of non-zero elements in the array.