Function soapysdr_sys::SoapySDRDevice_listFrequencies

pub unsafe extern "C" fn SoapySDRDevice_listFrequencies(
    device: *const SoapySDRDevice,
    direction: c_int,
    channel: usize,
    length: *mut usize
) -> *mut *mut c_char

List available tunable elements in the chain. Elements should be in order RF to baseband. \param device a pointer to a device instance \param direction the channel direction RX or TX \param channel an available channel \param [out] length the number names \return a list of tunable elements by name