Rules for coding IEASYMxx

Follow these rules when coding IEASYMxx:

Define new system symbols that are 1- through 8 characters long, excluding the required ampersand and the optional period. For example, you can define a system symbol called &PAGESYM3, which contains an 8-character name, using the following SYMDEF statement:
```
SYMDEF(&PAGESYM3='LOCAL3')
```
Do not define resolved substitution texts that are longer than system symbol names (including the required ampersand and excluding the optional period). Before being resolved, a substitution text can contain other system symbols that extend its length beyond the length of the symbol name. However, the substitution text for those symbols must resolve to form a string that is less than the length of the symbol name.
For example, consider the &PAGESYM3 system symbol definition:
```
SYMDEF(&PAGESYM3='LOCAL3')
```
The LOCAL3 substitution text above is valid because it contains six characters, which is less than the 9 characters in the symbol name, &PAGESYM3 (note that the optional period is not included). The following definition is also valid:
```
SYSNAME(SYS1)
SYMDEF(&PAGESYM3='LOC&SYSNAME.3')
```
Note that although the LOC&SYSNAME3 substitution text appears longer than the &PAGESYM3 symbol, the &SYSNAME system symbol in LOC&SYSNAME3 resolves to a character string that makes the final resolved substitution text, LOCSYS13, shorter than the symbol name.

If you specify a substitution text that, when resolved, is longer than a symbol name, the system will prompt for a valid substitution text.

Recommendation: Define system symbols that are eight characters long (the maximum) so you can define substitution texts that are up to nine characters long (the eight characters in the system symbol name plus the ampersand at the beginning of the name).
Do not define new system symbols that begin with the characters SYS. Those names are reserved for existing system symbols (like &SYSNAME).
You can specify an optional period at the end of a system symbol definition. For example, both of the following statements are valid and define the same system symbol:
```
SYMDEF(&PAGESYM1='LOCAL1')
SYMDEF(&PAGESYM1.='LOCAL1')
```
When coding a single quotation mark as part of a substitution text for an installation-defined static system symbol, specify two consecutive single quotation marks. In the following example, &SYMBOL4 is assigned the string O'HARE:
```
SYMDEF(&SYMBOL4='O''HARE')    /* &SYMBOL4 is assigned O'HARE  */
```
If you intend to use a system symbol to represent a parmlib member suffix in IEASYSxx, see the description of IEASYSxx in this information for special considerations.

If the system finds an error in IEASYMxx, the system will issue message IEA013E. If a statement in error applies to the processor or LPAR on which this system is being initialized, the system will then issue message IEA011A to prompt for a new IEASYMxx parmlib member.