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C:Macros的加工商?
原标题:C: Preprocessor in Macros?

是否有办法在宏观范围内使用加工前关键词? 如果存在某种逃逸性质,我不知道。

例如,我要作一个扩大这方面内容的宏观:

#ifdef DEBUG
    printf("FOO%s","BAR");
#else
    log("FOO%s","BAR");
#endif

本节内通知系按来文照登。

PRINT("FOO%s","BAR");

这样做是可能的,还是我只是虚幻的(而且每当我想显示一种丑恶的信息时,我就不得不取消程序前的有条件)?

最佳回答

您不能直接这样做,但你可以界定<代码>PRINT<>/code>,宏观上有所不同,取决于对<代码>DEBUG的定义:

#ifdef DEBUG
    #define PRINT(...) printf(__VA_ARGS__)
#else 
    #define PRINT(...) log(__VA_ARGS__)
#endif
问题回答

换言之,它围绕的是:

#ifdef DEBUG
    #define PRINT printf
#else
    #define PRINT log
#endif

你们不要cra,而是从错误的角度来看待。 你可能没有宏观扩大,以提出更多的加工前方论点,但你可以有条件地根据加工前的论点确定一个宏观:

#ifdef DEBUG
# define DEBUG_PRINT printf
#else
# define DEBUG_PRINT log
#endif

如果你有单体宏观,你可以读到<条码>。 这两种方式都是行之有效的。 第二让你使用职能点,但我无法想象,为什么你需要这样做。





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