如何不变量参数Functioncall宏观界定？ [英] How to does a variable argument Functioncall as macro define?

问题描述

想象一下，我有一个调试的源文件，
这是这样的：

Imagine, I have a debug source file, which is like this:

#if _OWN_DEBUG_LEVEL != 0

    void DebugLogMsg (DebugStruct_t *DebugStruct, size_t sizeID, char const *szFormat, ...);

#else

    #define DebugLogMsg(_Expression1, _Expression2, _Expression3) ((void)0) 

#endif

在这种情况下，我真的不关心其他参数的功能，但对于这种情况？

In this case I do not really care about the additional arguments to the function, but what about this case?

#if _OWN_DEBUG_LEVEL > 0

    #undef DebugLogMsg1

    #define DebugLogMsg1(_Expression1, _Expression2, _Expression3) \ 
        DebugLogMsg(_Expression1, _Expression2, _Expression3)

#endif

在这种情况下，我不太清楚...当我调用宏是这样的：

In this case I'm not quite sure... when I call the macro like this:

DebugLogMsg1(pointer, var, pointer, 1, 2, 3);

将 _ex pression3 是请客的那会是指针，1，2，3 还是什么将是确切的行为？

will _Expression3 be treat as would it be pointer, 1, 2, 3 or what would be the exact behaviour?

推荐答案

这是做不到的。您应该使用复杂的宏：

It just wouldn't work. You should use variadic macros:

#define DebugLogMsg1(a, b, c, ...) DebugLogMsg(a, b, c, __VA_ARGS__)

或许更好（因为它不会导致尾随逗号的问题）：

Or perhaps better (since it doesn't cause issues with trailing commas):

#define DebugLogMsg1(...) DebugLogMsg(__VA_ARGS__)

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