lo_open_by_fileid
error = lo_open_by_fileid(xc, fileid, INV_READ, &fd);
error = lo_open_by_fileid(xc, fileid, INV_WRITE, &fd);
error = lo_open_by_fileid(xc, fileid, INV_READ, &fd);
error = lo_open_by_fileid(xc, fileid, INV_READ|INV_WRITE, &fd);
error = lo_open_by_fileid(xc, fileid, INV_READ, &fd);
int lo_open_by_fileid(struct Xconn *, fileid_t, int, int *);