Use the #define directive to substitute text in a source file. Then use the #undef directive to limit the range of the substitution.

The #define directive can also used to define identifiers whose values can be tested in an #if...#elif...#else...#endif directive.

If an #undef directive is specified after the #define directive, all occurrences of <identifier> between the #define directive and the #undef directive will be replaced with the value of value. If no #undef directive is specified, all occurrences of <identifier> between the #define directive and the end of the source file will be replaced.

If the region over which the substitution occurs includes any #include directives, any occurrences of <identifier> in those include files will also be replaced with the value of <value>. You can use this feature to create include files that contain variables whose values will be defined in the source file.

If <value> is supplied, enclose it in quotation marks unless a numeric identifier is being defined for use with an #if...#elif...#else...#endif directive.

If <value> is not supplied, <identifier> is replaced with a zero length string.

The search for <identifier> is case-sensitive, and identifiers that occur within string literals (quoted strings) are not replaced.

For more information about using the#define directive in data management scripts, see Using text substitution in the DMS file.

The following example uses the #define directive to replace text in an include file. All occurrences of “TargetDDF” and “TargetMDD” in the include file will be replaced with the file locations defined in the two #define directives. The two #undef directives ensure that any further occurrences of “TargetDDF” and “TargetMDD” in the source file will not be replaced: