Question

#define STR_A  abc
#if STR_A == abc   //I want to make some check here
    do something A
#else
    do something B
#endif

Can I check what the STR_A defined?

Answer 1

If you want to check if STR_A is defined to the token abc (which by itself shouldn’t be another macro) you can help yourself with some tricks

#define STR_A_TESTER_abc 1
#define CONCAT(A, B) A ## B
#define STR_A_TESTER CONCAT(STR_A_TESTER_, STR_A)

#if STR_A_TESTER
// do whatever
#else
// or other
#endif