Calling Help from a DLL or XLL

• HELPCALL.C contains the C source code for CallHelp, a function that could be used in a DLL or XLL to call Microsoft Windows Help, using the Windows API WinHelp function. CallHelp only displays a Help topic, but you can expand it to use the WinHelp API to more fully control Microsoft Help.
• HELPCALL.DEF, HELPCALL.MDP and HELPCALL.MAK are files that, along with HELPCALL.C, you will need if you want to compile your own HELPCALL.DLL file.

• HELPCALL.DLL is the compiled DLL file.
• HELPCALL.XLM contains a two-line macro that calls the CallHelp function (defined in HELPCALL.C) in the compiled DLL. Use this macro to verify that the DLL works.

Also, from a DLL or XLL, you can use the xlfHelp function from the Microsoft Excel C API.