C预处理程序优先级

Question

I have the following problem:

extern void func_name(const char *f);  
#define EXPECT(f) func_name(#f)  
#define foo bar  

void main()  
{  
     EXPECT(foo);  
}  

So, the

EXPECT(foo);

will be actually evaluated to

func_name("foo");

What I actually need is to convert 'foo' to 'bar', ie the code to become

func_name("bar");

So I kind of want to do this:

#define "foo" "bar"

But this does not work, because macro names must be identifiers. I also tried to find a way to change the preprocessor precedence, so my macro will be replaced first, but didn't find a way.

The perfect solution will not change main() at all.

Answer 1

#define S(x) #x
#define EXPECT(f) func_name(S(f))