About Structures

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Microsoft Corporation

Updated June 10, 1999

The HTML Help API provides several objects that you work with using data structures.

When working with a structure, it is recommended that you use a Win32 function such as ZeroMemory, memcpy, or memset to clear out the address space of a structure that has been declared. This ensures that you start with a known quantity before making any modifications. For example, the following code fragment uses memset to make a copy of an HH_WINTYPE structure:

HH_WINTYPE hhWinType;                   //Create new wintype.
           HH_WINTYPE *phhWinType;      //Create a pointer to this wintype.
           memset(phhWinType,           //Requires "memory.h" header be included in the calling application.
                  0,
                  sizeof(HH_WINTYPE)); 
           HtmlHelp(hwnd,
                    "c:\\help\\MyHelpFile.chm>main",
                    HH_GET_WIN_TYPE,
                    (DWORD)&phhWinType);
           hhWinType = *phhWinType;    //Create a copy so we don't write directly.

Note

• The Win32 functions such as ZeroMemory,memcpy, or memset do not make a deep copy of the structure. Developer-written copy constructors perform proper deep copies for OOP/C++ classes and objects.

Structures quick reference

Category	Structure
Window types	HH_POPUP HH_WINTYPE
ALink name/KLink keyword lookups	HH_AKLINK
Notification messages	HHN_NOTIFY HHNTRACK
Full-text search	HH_FTS_QUERY
Error tracking	HH_LAST_ERROR

	About the HTML Help API