Function ZL_Compressor_Node_getBaseNodeID 

pub unsafe extern "C" fn ZL_Compressor_Node_getBaseNodeID(
    cgraph: *const ZL_Compressor,
    node: ZL_NodeID,
) -> ZL_NodeID

@returns If the provided @p node was created by modifying another existing node, the ZL_NodeID of that other node. Otherwise, ZL_NODE_ILLEGAL.