Common Desktop Environment: Help System Author's and Programmer's Guide

Including Special Characters

Many special characters and symbols are available within HelpTag. You display a particular character by entering the appropriate entity reference.

Some special character entities are declared in the file helpchar.ent. The helpchar.ent file is located in the /usr/dt/dthelp/dthelptag directory. To access these characters, either copy the particular entity declaration into your own volume, or include the entire helpchar.ent file. Unused entity declarations are ignored.

Refer to Chapter 6, Summary of Special Character Entities, for a complete list of the available characters.

To Include a Special Character

  1. Refer to Chapter 6, Summary of Special Character Entities, to determine the entity name for the character you want to display. Also, note whether it is a built-in special character.

  2. If the character is not a built-in special character, add the following two lines among your other entity declarations (where entity-name is a meaningful name to you):

    <!entity entity-name FILE  "helpchar.ent">  &entity-name;

    Also, add this line to your helptag.opt file:


    If the character is built into HelpTag, you can skip step 2.

  3. Wherever you want to display the special character, enter its entity reference:



The entity for the copyright symbol (©) is a built-in special character, so all you have to do to display it is use this entity:


To display the uppercase greek letter sigma, you must first include the helpchar.ent file (at the top of your help volume with your other entity declarations) as shown here:

<!entity  SpecialCharacterEntities  FILE   "helpchar.ent">  

Then you can place the following entity reference where the sigma character is to appear:


As with any entity, case is not significant in the entity names for special characters.

See Also