#### 18.11.2 Determining whether you need map and alias files

Markers

If you use PI markers for CSH destinations, you need both a map file and an alias file:

map file | Associates each numeric ID in the application with a symbolic ID in your document, where the symbolic ID is the relevant PI marker text.
alias file | Associates each symbolic ID in your document with the .htm file where the relevant PI marker is located.

When you use PI markers, developers should use the HH_HELP_CONTEXT API, and specify topics by numeric ID. You need the map and alias files to associate their numeric IDs with your symbolic IDs. Each time you convert your DITA document to HTML Help, DITA2Go uses the symbolic IDs to generate an alias file; see §18.11.4 Creating an alias file for CSH links. Usually the developers provide the map file.

When developers use the HH_HELP_CONTEXT API, the application must send a numeric ID, and you must have the map file in your project to interpret the numeric ID. The developers need only the map file. You need only to add to your HTML Help project file the name of the map file and the name of the alias file, before compiling. You can do this via configuration setting; see §18.11.3 Specifying and generating a map file for CSH links.

Previous Topic: 18.11.1 Inserting CSH destinations in your document

Next Topic: 18.11.3 Specifying and generating a map file for CSH links

Parent Topic: 18.11 Setting up CSH for HTML Help

Sibling Topics:

18.11.1 Inserting CSH destinations in your document

18.11.3 Specifying and generating a map file for CSH links

18.11.4 Creating an alias file for CSH links

18.11.5 Understanding alias-file entries

18.11.6 Producing a list of aliases and associated topic titles