raw_ref type?

[brandonros]

// PassThruGetLastError
typedef struct _get_last_error_rpc_response {
  long retVal;
  RPCLIB_MSGPACK::type::raw_ref errorMsgRef;
  MSGPACK_DEFINE(
    retVal,
    errorMsgRef
  )
} get_last_error_rpc_response;

Example

[gfx]

Can you describe what you want in the messagepack-javascript? Your example looks like C code.

[brandonros]

I am happy to say that messagepack-javascript correctly handled creating it to Uint8Array with no manual intervention, thanks!