Under Windows 3.x, the multimedia services were supported by the MmSystem.DLL. Under Windows 98/95/NT, these services are now supported by Win32 WinMM and the WinMM.DLL library. If you are porting a multimedia application from Windows 3.x to 98/95/NT, be sure to include the MmSystem.H header and to link WinMM.LIB instead of MmSystem.LIB.
Also, the Multimedia Extensions were originally released as a separate product enhancing Windows 3.0 with the MCI_OPEN_PARMS structure used to access multimedia services. Later, under Windows 3.1, the MCI_OPEN_PARMS structure changed the second and third fields from type WORD to the polymorphic type UINT and then, for Win32, to the newly defined MCIDEVICEID type.
If you are porting multimedia applications, keep in mind that a number of type changes have occurred, even though the functions and structures remain similar across the several versions of the operating system.
NOTE
See Chapter 37 for more information about developing multimedia applications.
In this appendix, we’ve covered many of the more common Windows 3.x-to-98/95/NT conversions and what types of changes may be necessary. Of course, there are many other possible differences between Windows 3.x and 98/95/NT that can affect program conversion. These are discussed and illustrated throughout the chapters in this book.