This example calls WinRegisterUserDatatype to register a class or returns FALSE if an error occurs.

#define INCL_WINMESSAGEMGR
#define INCL_WINTYPES
#include <OS2.H>
#define DTYP_MINE DTYP_USER + 1

HAB hab;
LONG  asTypes[3] = {DTYP_CHAR,
                    DTYP_STRL,
                    DTYP_STR32};

WinRegisterUserDataType(hab,
                        DTYP_MINE,
                        3,
                        asTypes);