The EntityAddSymbol function adds the equivalent symbol for an entity (the text used to replace the entity) to an entity codec control structure.

The argument ptr points to the control structure. The text that defines the symbol is stored in the structure pointed to by the argument entity.

An entity is often used as short hand for repeated text, to refer to symbols that would otherwise confuse the XML passer, such as "<" or ">", or to refer to external data.The entity codec encodes and decodes entity/symbol pairs.