Printing name and value of a macro

Question

I have a C program with a lot of optimizations that can be enabled or disabled with #defines. When I run my program, I would like to know what macros have been

Answer 1

As long as you are willing to put up with the fact that SOMESTRING=SOMESTRING indicates that SOMESTRING has not been defined (view it as the token has not been redefined!?!), then the following should do:

#include 

#define STR(x)   #x
#define SHOW_DEFINE(x) printf("%s=%s\n", #x, STR(x))

#define CHARLIE -6
#define FRED 1
#define HARRY FRED
#define NORBERT ON_HOLIDAY
#define WALLY

int main()
{
    SHOW_DEFINE(BERT);
    SHOW_DEFINE(CHARLIE);
    SHOW_DEFINE(FRED);
    SHOW_DEFINE(HARRY);
    SHOW_DEFINE(NORBERT);
    SHOW_DEFINE(WALLY);

return 0;
}

The output is:

BERT=BERT
CHARLIE=-6
FRED=1
HARRY=1
NORBERT=ON_HOLIDAY
WALLY=