This is part of Win16 API which allow to create versions of program from one source code to run under OS/2 and Win16. Under OS/2 program can be running under Win-OS/2 if program is Windows NE executable, and with help on Windows Libraries for OS/2, if it is OS/2 NE executable. Here is a WLO to OS/2 API mapping draft

Ordinal	Name	Description	Status	Version
001	LZCOPY	Done
002	LZOPENFILE	Done
003	LZINIT	Done
004	LZSEEK	Done
005	LZREAD	Done
006	LZCLOSE	Done
007	LZSTART	Done
008	COPYLZFILE	Done
009	LZDONE	Done
010	GETEXPANDEDNAME	Done