Ifndef

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#ifndef

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)

Remarks

Differences from QB

• New to FreeBASIC

See also

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

Examples

#ifndef __MYFILE_BI__

#define __MYFILE_BI__

    ' Declarations

#endif

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Category: Preprocessor
Kind: keyword

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Reproduced from the FreeBASIC Wiki Manual under the GNU Free Documentation License 1.3 — with no Invariant Sections, no Front-Cover Texts and no Back-Cover Texts. Copyright © the FreeBASIC project and wiki contributors. See License.