Can a C macro definition refer to other macros?

Question

What I\'m trying to figure out is if something such as this (written in C):

#define FOO 15
#define BAR 23
#define MEH (FOO / BAR)
         


        

Answer 1

Yes, and there is one more advantage of this feature. You can leave some macro undefined and set its value as a name of another macro in the compilation command.

#define STR "string"
void main() { printf("value=%s\n", VALUE); }

In the command line you can say that the macro "VALUE" takes value from another macro "STR":

$ gcc -o test_macro -DVALUE=STR main.c
$ ./test_macro

Output:

value=string

This approach works as well for MSC compiler on Windows. I find it very flexible.