Function nanocbor_get_null

pub unsafe extern "C" fn nanocbor_get_null(
    cvalue: *mut nanocbor_value_t,
) -> c_int

@brief Retrieve a null value from the stream

This function checks if the next CBOR value is a NULL value and advances to the next value if no error is detected

@param[in] cvalue CBOR value to decode from

@return NANOCBOR_OK on success @return negative on error