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.
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; &entity-name;
Also, add this line to your helptag.opt file:
search=/usr/dt/dthelp/dthelptag
If the character is built into HelpTag, you can skip step 2.
Wherever you want to display the special character, enter its entity reference:
&entity-name;
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"> &SpecialCharacterEntities;
Then you can place the following entity reference where the sigma character is to appear:
&Usigma;
As with any entity, case is not significant in the entity names for special characters.