Invokes the Help facility

(help [helpfile [topic [command]]]) 



A string naming the Help file. The file extension is not required with the helpfile argument. If a file extension is provided, AutoCAD looks only for a file with the exact name specified.

If no file extension is provided, AutoCAD looks for helpfile with an extension of .chm. If no file of that name is found, AutoCAD looks for a file with an extension of .hlp.


A string identifying a Help topic ID. If you are calling a topic within a CHM file, provide the file name without the extension; AutoCAD adds an .htm extension.


A string that specifies the initial state of the Help window. The command argument is a string used by the uCommand (in HTML Help) or the fuCommand (in WinHelp) argument of the HtmlHelp() and WinHelp() functions as defined in the Microsoft Windows SDK.

For HTML Help files, the command parameter can be HH_ALINK_LOOKUP or HH_DISPLAY_TOPIC. For Windows Help files, the command parameter can be HELP_CONTENTS, HELP_HELPONHELP, or HELP_PARTIALKEY.

Return Values

The helpfile string, if successful; otherwise nil. If you use help without any arguments, it returns an empty string ("") if successful, and nil if it fails.

The only error condition that the help function returns to the application is the existence of the file specified by helpfile. All other error conditions are reported to the user through a dialog box.


The following code calls help to display the information on MYCOMMAND in the Help file achelp.chm:

(help "achelp.chm" "mycommand")
See Also