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I'm trying to write a macro that generates code for an object pool for any given class of objects in C. I keep getting error: '#' is not followed by a macro parameter whenever I run the preprocessor

I've tried replacing x##y with:

#define CONCAT1(x, y) x##y
#define CONCAT2(x, y) CONCAT1(x, y)
as this was suggested in a similar question
#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)\
Expected: Code goes through the preprocessor and gives function prototypes for objects of type "CLASS"

Actual Results: 
  
error: '#' is not followed by a macro parameter

   #define DECLARE_POOL(CLASS, LEVEL1, LEVEL2) {\
                have your tried outputting the code after the preprocessing. perhaps via the '-E' option in gcc
– user3629249
                Sep 27, 2019 at 4:44
                @bostonbrooks: i guess you'll need to expand it all out. I'm not sure what you are really trying to do.
– rici
                Sep 26, 2019 at 3:04
                @BostonBrooks I'd advise to place all code generation completely outside your C source. Make a separate program for that. Because these kind of icky macros have  about 99% chance of backfiring.
– Lundin
                Sep 26, 2019 at 10:49
        
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