An application can send a HELP_COMMAND parameter in the WinHelp function call that specifies a macro to execute. The WinHelp function uses the following C-language syntax:
BOOL WinHelp (hWnd, lpHelpFile[>WindowName], wCommand, dwData)
When sending a macro request, the dwData parameter should point to a null-terminated string that contains the macro. The macro string can have as many as 255 characters.
The following example uses a Help macro to specify the context string IDM_HELP_KEYBOARD for the Keyboard topic in MYHELP.HLP:
case IDM_HELP_KEYBOARD:
WinHelp (hWnd, "myhelp.hlp", HELP_COMMAND,
(LPSTR) "JumpID(\"myhelp.hlp\",\"IDM_HELP_KEYBOARD\")");
return 0L;
For more information about the WinHelp function, see Chapter 19, “The WinHelp API.”