LIB returns an exit code (also called return code or error code) to the operating system or the calling program. You can use the exit code to control the operation of batch files or makefiles.
| Code | Meaning |
| 0 | No error. |
| 2 | Program error. Commands or files given as input to the utility produced the error. |
| 4 | System error. The library manager encountered one of the following problems: |
| There was insufficient memory. | |
| An internal error occurred. | |
| The session was interrupted by the user. |