Data Definition Language (DDL) Reference Manual

Named Constants
Data Definition Language (DDL) Reference Manual—529431-004
4-5
Existing Constants
Existing Constants
When using the name of an existing constant as the value in a CONSTANT statement:
•
You can specify a DDL constant name instead of a literal value in the VALUE
clause of a CONSTANT statement whether the constant name identifies a string
constant, a numeric constant, or a product version constant.
•
When the name identifies a previously defined string constant, the new value is
identical to the value of the string constant.
•
When the name identifies a previously defined product version constant, the new
value is identical to the value of the product version constant.
•
When an existing numeric constant is named in the definition of another DDL
numeric constant, certain rules apply:
°
If the CONSTANT statement does not include a TYPE clause, the constant
being defined inherits the type of existing-constant.
°
If the CONSTANT statement has a TYPE clause, its specified type overrides
the type of existing-constant.
°
If a TYPE clause in the CONSTANT statement overrides the type of
existing-constant, the value of existing-constant must be
consistent with the specified type.
C
When generating C source code from CONSTANT statements:
•
If you request C source-code output, by giving the C command, the DDL compiler
generates #defines for named constants.
•
The DDL compiler converts any hyphen in the constant name to an underscore (_)
in the #define name.
•
The DDL compiler generates uppercase letters for names that follow #define.
•
For a string constant, the DDL compiler generates a #define of this form:
#define CONSTANT-NAME string-literal
•
For a numeric constant, the DDL compiler generates a #define of this form:
#define CONSTANT-NAME numeric-constant
•
For a product version constant, the DDL compiler generates a #define that
contains the product version number.