Windows 3.1 includes many new functions as well as enhancements to existing Windows functions. Windows has also added many new styles and messages to existing user controls. Following are some of the additions and enhancements:
Drag-drop feature (SHELL.DLL)
Registration database (SHELL.DLL)
Dynamic Data Exchange Management Library (DDEML.DLL)
Common dialog boxes (COMMDLG.DLL and international versions of the library)
Object linking and embedding (OLECLI.DLL, OLESVR.DLL, SHELL.DLL)
Data decompression (LZEXPAND.DLL)
System resources stress-testing (STRESS.DLL)
File installation and version checking (VER.DLL and VER.LIB)
Tool help (TOOLHELP.DLL)
Windows Help (WINHELP.EXE and WINHELP.HLP)
TrueType fonts
New printer functions
Device-independent bitmap driver (DIB.DRV)
Installable drivers
Enhanced messages, styles, and functions
Most of the new Windows 3.1 functions are included in several new DLLs. The appropriate DLL must be present for a program to use the new functions.
For more information about any of these new features, see the Microsoft Windows Programmer's Reference.