#IFNDEF

• Source: https://www.freebasic.net/wiki/wikka.php?wakka=KeyPgPpifndef
• Last revised: 2023-10-02

---

Preprocessor conditional directive

Syntax

#ifndef symbol

' Conditionally included statements

#endif

Description

Conditionally includes statements at compile time.

Statements within the #ifndef...#endif block are included if symbol is not defined and excluded (ignored) if symbol is defined.

#ifndef symbol is equivalent to #if Not defined(symbol)

Examples

start GeSHi

#IFNDEF __MYFILE_BI__
#DEFINE __MYFILE_BI__
    ' Declarations
#ENDIF

end GeSHi

Differences from QB

• New to FreeBASIC

See also

• #define
• #macro
• #if
• #else
• #elseif
• #elseifdef
• #elseifndef
• #endif
• #ifdef
• #undef
• defined

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