Language Reference Guide > Language Reference Guide > Preprocessing Your 4GL Code > Preprocessor > The #ifndef - #endif Statement
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The #ifndef - #endif Statement
The #ifndef statement can be used to test whether a name has not been defined as a macro variable by #define. The syntax for this statement is:
#ifndef $variable
...
#else
...
#endif
The #ifndef statement is TRUE if the macro variable has not been defined.
Last modified date: 12/20/2023