DOCERR: Wrong WinHelp Declaration in Windows Ver 3.1 API Ref (108036)

SUMMARY

This article corrects a documentation error for the WinHelp function call as described in the Windows version 3.1 API Reference help file that shipped with Microsoft Visual Basic version 3.0 for Windows.

MORE INFORMATION

The declaration is incorrectly shown as:

Declare Function WinHelp Lib "User" (ByVal hWnd As Integer,
                         ByVal lpHelpFile As String,
                         ByVal wCommand As Integer,
                         dwData As Any) As Integer

The correct declaration is as follows:

Declare Function WinHelp Lib "User" (ByVal hWnd As Integer,
                         ByVal lpHelpFile As String,
                         ByVal wCommand As Integer,
                         ByVal dwData As Any) As Integer

NOTE: Each Declare statement must be entered as one, single line. Notice that the "ByVal" keyword was omitted from the last parameter in the online reference. This means that the function is passing the last parameter "dwData" by reference. It needs to be passed by value.

The most common error that occurs when using the incorrect declaration is a message box stating "Help topic does not exist."