c - 错误: '#' is not followed by a macro parameter

Question

我正在尝试编写一个宏，为 C 中任何给定对象类的对象池生成代码。每当我运行预处理器时，我总是收到错误:'#'后面没有宏参数

我尝试将 x##y 替换为:

#define CONCAT1(x, y) x##y
#define CONCAT2(x, y) CONCAT1(x, y)

因为这是在类似问题中建议的

#define CONCAT1(x, y) x##y
#define CONCAT2(x, y) CONCAT1(x, y)

#define DECLARE_POOL(CLASS, LEVEL1, LEVEL2) {\
\
    #define CONCAT2(CLASS, _Pool_Level1) LEVEL1\
    #define CONCAT2(CLASS, _Pool_Level2) LEVEL2\
\
    CLASS* CONCAT2(CLASS, _Pool)[LEVEL1] = { 0 };\
\
    int CONCAT2(CLASS, _Available_Head) = -1;\
    int CONCAT2(CLASS, _Available_Tail) = -1;\
\
    int CONCAT2(CLASS, _In_Use_Head) = -1;\
    int CONCAT2(CLASS, _In_Use_Tail) = -1;\
\
    int CONCAT2(CLASS, _Increase_Pool)(int Level1_Address){\
\
    }\
\
    int CLASS(int Address) {\
\
    }\
\
    int CONCAT2(CLASS, _Delete)(int Address) {\
\
    }\
\
    int CONCAT2(CLASS, s)(int Address)\
\
    }\
\
    int CONCAT2(CLASS, _Save_All)(void)\
\
    }\
\
    int CONCAT2(CLASS, _Restore_All)(void)\
\
    }\
    int CONCAT2(CLASS, _Free_All)(void)\
\
    }\
}

预期:代码通过预处理器并给出“CLASS”类型对象的函数原型(prototype)
实际结果:

error: '#' is not followed by a macro parameter
#define DECLARE_POOL(CLASS, LEVEL1, LEVEL2) {\

Answer 1

您不能在宏内使用#define。或任何其他预处理器指令，就此而言。