C language compares whether two macros are equivalent

I want to judge that if a macro is defined as X, do action A, and when defined as Y, do action B. It"s okay to write like this

-sharpdefine X ((void*)0)
-sharpdefine M X
-sharpif M==X
    -sharperror("Equal!");
-sharpelse
    -sharperror("Not equal");
-sharpendif

is there any way to make it work, or to achieve this function in disguise?

CPP c
Jul.04,2022
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1c10150-32cb4.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1c10150-32cb4.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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