Define substitution string.
DEFINE symbol string
The DEFINE directive is used to define substitution strings that are used on all following source lines. All succeeding lines are searched for an occurrence of symbol, which are replaced by string. This directive is useful for providing better documentation in the source program.
The symbol must adhere to the restrictions for non-local labels. That is, it cannot exceed 512 characters, the first of which must be alphabetic, and the remainder of which must be either alphanumeric or the underscore(_). A warning results if a new definition of a previously-defined symbol is attempted. The Assembler output listing shows lines after the DEFINE directive has been applied, and therefore redefined symbols are replaced by their substitution strings (unless the NODXL option in effect; see the OPT directive).
Macros represent a special case. DEFINE directive translations are applied to the macro definition as it is encountered. When the macro is expanded any active DEFINE directive translations are again applied. DEFINE directive symbols that are defined within a section are only applied to that section.
A label is not allowed with this directive.
DEFINE ARRAYSIZ '10*5'
DS ARRAYSIZ
The above two lines would be transformed by the Assembler to the following:
DS 10*5