As it says at the bottom of the documentation, they're declared in winuser.h. That is an include file that comes with the Win32 SDK (included with Visual C++, for example). You can get the SDK by itself here (for free):
http://www.microsoft.com/msdownload/platformsdk/sdkupdate/
Alternatively, you can get something like APIViewer to tell you the values of constants. http://www.activevb.de/rubriken/apiviewer/index-apiviewer.html#anchor3.
http://www.microsoft.com/msdownload/platformsdk/sdkupdate/
Alternatively, you can get something like APIViewer to tell you the values of constants. http://www.activevb.de/rubriken/apiviewer/index-apiviewer.html#anchor3.