CC78K4 Datasheet, PDF (141/523 Pages) NEC – CC78K4 Ver.2.30 or Later, C Compiler Language

CHAPTER 9 PREPROCESSING DIRECTIVES (COMPILER DIRECTIVES)
(4) #ifndef directive
Conditional Translation Directives
#ifndef
FUNCTION
The #ifndef directive is equivalent to:
#if !defined (identifier)
If the identifier has never been defined with the #define directive, the source code between #ifndef and #endif
will not be translated.
SYNTAX
#ifndef identifier line feed group
EXAMPLE
#define ON
#ifndef ON
:
#endif
EXPLANATION
In the above example, the identifier “ON” has been defined with the #define directive. Thus, the source code
between #ifndef and #endif will be discarded in the translation phase. If the identifier “ON” has never been
defined, the source code between #ifndef and #endif will be translated.
User’s Manual U15556EJ1V0UM
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