dataconn
dout = dataconn("MLSD", (off_t)-1, "w");
FILE *dataconn(const char *, off_t, const char *);
dout = dataconn(dispname, st.st_size, "w");
din = dataconn(name, (off_t)-1, "r");
dout = dataconn("file list", (off_t)-1, "w");
dout = dataconn("file list", (off_t)-1,
FILE *dataconn(const char *);
din = dataconn("r");
dout = dataconn(lmode);