Answer by HolyBlackCat for How to compare string when precompile

You have two options:

1. Use numbers instead of strings, and give them names using macros:

   #define HELLO 1#define ASDASD 2#define MY_MACRO HELLO#if MY_MACRO == HELLO// ...#endif

2. Don't use preprocessor, use a plain if (or if constexpr, the only difference here is that the latter forces the condition to be a compile-time constant). This means that all branches have to be valid (have to compile) regardless of which one is choosen:

   #define MY_MACRO "hello"int main(){    if constexpr (MY_MACRO == std::string_view("hello"))    {    }}

   Or make MY_MACRO a global constexpr std::string_view variable if you don't need to override it with compiler flags.