Function lightgbm_sys::LGBM_DatasetGetNumData

pub unsafe extern "C" fn LGBM_DatasetGetNumData(
    handle: DatasetHandle, 
    out: *mut c_int
) -> c_int

\brief Get number of data points. \param handle Handle of dataset \param[out] out The address to hold number of data points \return 0 when succeed, -1 when failure happens