Xcode 中 #elseifdef 的预处理指令无效
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Invalid preprocessing directive for #elseifdef in Xcode
提问by Lukasz
Why:
为什么：
#ifdef SOME_TARGET_FLAG
<some code here>
#elseifdef SOME_ANOTHER_TARGET_FLAG
<some another code here>
#endif
produces "Invalid preprocessing directive" preprocess compilation error?
产生“无效的预处理指令”预处理编译错误？
SOME_TARGET_FLAG and SOME_ANOTHER_TARGET_FLAG are just some "Other C-flags" defined in target build settings (-D<FLAG_NAME>pattern).
SOME_TARGET_FLAG 和 SOME_ANOTHER_TARGET_FLAG 只是在目标构建设置（-D<FLAG_NAME>模式）中定义的一些“其他 C 标志” 。
Is #elseifdefdirective not supported by Xcode?
是#elseifdef指令不被支持的Xcode？
回答by justin
Is #elseifdef directive not supported by Xcode?
Xcode 不支持 #elseifdef 指令吗？
It is not. Use this instead:
它不是。改用这个：
#elif defined(SOME_ANOTHER_TARGET_FLAG)
回答by hburde
Its not supported as indicated by the error message. See 'the C preprocessor' - https://developer.apple.com/library/mac/#documentation/DeveloperTools/gcc-4.2.1/cpp/index.html#//apple_ref/doc/uid/TP40007092(conditional compilation).
如错误消息所示，它不受支持。请参阅“C 预处理器” - https://developer.apple.com/library/mac/#documentation/DeveloperTools/gcc-4.2.1/cpp/index.html#//apple_ref/doc/uid/TP40007092（条件编译）。
