epio/mantrid — comment on commit 909a174798cd1e1831c258ac288259904d94ed59
File: mantrid/actions.py line 72
By andrewgodwin:

The manpage says "If the transfer was successful, the number of bytes written to out_fd is returned. On error, -1 is returned, and errno is set appropriately.", so I _think_ it's all-or-nothing.