The output files produced by LIB depend on the mode in which it is being used, as shown in the following table.
| Mode | Output |
| Default (building or modifying a library) | COFF library (.LIB) |
| Extracting a member with /EXTRACT | Object (.OBJ) file |
| Building an export file and import library with /DEF | Import library (.LIB) and export (.EXP) file |