IMPLIB is used to generate an import library (.LIB) file. IMPLIB takes a module definition file (.DEF) as input. For each export definition in the .DEF file, IMPLIB generates a corresponding import definition.

The .LIB file generated by IMPLIB is used as input to LINK386, which creates an executable (.EXE) file. The .LIB file provides LINK386 with information about imported dynamic link functions.