Components of the Help System

Components of the Help System

As you might expect, a large number of files interact to make online Help work. The
final product, which you deliver to your user, is the Help file, with the .hlp extension.
It is built from component files. In the list that follows, appname refers to the name of
your application's .exe file. If no name appears, there might be more than one file with a
variety of names. The component files produced by AppWizard are as follows:
h These Header files define resource IDs and Help topic IDs for use
within your C++ code.
.hm These Help Mapping files define Help topic IDs. appname.hm is
generated every time you build your application - don't change it
yourself.
.rtf These Rich Text Format files contain the Help text for each Help
topic.
appname.cnt You use this table of contents file to create the Contents tab of
the Help Topics dialog box. (You should distribute this contents
file with your application in addition to the Help file.)
appname.hpj This Help ProJect file pulls together .hm and .rtf files to
produce, when compiled, a .hlp file.

While being used, the Help system generates other files. When you uninstall your
application from the user's hard disk, be sure to look for and remove the following files,
in addition to the .hlp and .cnt files:
l appname.gid is a configuration file, typically hidden.
l appname.fts is a full text search file, generated when your user does a Find
through your Help text.
l appname.ftg is a full text search group list, also generated when your user does a
Find.
Help topic IDs are the connection between your Help text and the Help system. Your
program eventually directs the Help system to display a Help topic, using a name such as
HID_FILE_OPEN, and the system looks for this Help topic ID in the Help file, compiled
from the .rtf files, including the .rtf file that contains your Help text for that Help
topic ID. (This process is illustrated in Figure 11.4.) These topic IDs have to be defined
twice - once for use by the Help system and once for use by your program. When the Help
system is displaying a topic or the Help Topics dialog box, it takes over displaying other
Help topics as the user requests them, with no work on your part.
FIG. 11.4 Your program, the Help system, and your Help files all work together to display a topic.