Characteristics

In general, user-defined variables have the following characteristics:

User-defined variable names can be up to eight characters in length, not including the ampersand symbol (&); for example, &VARIABLE.
User-defined variables are resolved to mixed-case character data that is left-justified and stripped of trailing blanks.
If an undefined variable name appears as the first operand of a SET command, it is automatically defined as an uppercase transient variable.
If an undefined variable name appears within a quoted operand, it is resolved to a null string.
Values of transient variables are passed to any subroutine programs generated by the ACLPGM command.