Rules for coding IEASYMxx

Follow these rules when coding IEASYMxx:

Define new system symbols that are 1 to 16 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 is valid because it contains six characters, which are less than the 9 characters in the symbol name, &PAGESYM3. Notice that the optional period is not included. The following definition is also valid:
```
SYSNAME(SYS1)
SYMDEF(&PAGESYM3='LOC&SYSNAME.3')
```
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 prompts for a valid substitution text.
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 IEASYSxx (system parameter list) for special considerations.

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