From the code of ROOT in math/minuit/src/TMinuit.cxx version 5.34.14
| Error Code | Meaning |
|---|---|
| 0 | command executed normally |
| 1 | command is blank, ignored |
| 2 | command line unreadable, ignored |
| 3 | unknown command, ignored |
| 4 | abnormal termination (e.g., MIGRAD not converged) |
| 9 | reserved |
| 10 | END command |
| 11 | EXIT or STOP command |
| 12 | RETURN command |