#ELSEIFNDEF

• 来源: https://www.freebasic.net/wiki/wikka.php?wakka=KeyPgPpelseifndef
• 最后更新: 2023-10-02

---

预处理器条件指令

语法

#ifdef A

' Conditionally included statements if A is defined

#elseifndef B

' Conditionally included statements if both A and B are not defined

#else

' Conditionally included statements if A is not defined and B is defined

#endif

说明

#elseifndef 可添加到 #if 块中，以提供额外的条件。

#elseifndef symbol 等价于 #elseif Not defined(symbol)

示例

start GeSHi

#IFDEF A
    Print "A is defined"
#ELSEIFNDEF B
    Print "both A and B are not defined"
#ELSE
    Print "A is not defined and B is defined"
#ENDIF

end GeSHi

版本

• 自 fbc 1.20.0 起

与 QB 的区别

• FreeBASIC 新增

另请参阅

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

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