#include <stdio.h>

#define TYPE const char *
#define is_type(type_str, type) \
(strcmp(type_str, #type) == 0)

#define foo(type, param) \
foo_(#type, (void *) (param))

void foo_(TYPE type, void *param) {
  if(is_type(type, int)) {
    printf("%i\n", (int) param);
  } else if(is_type(type, char *)) {
    printf("%s\n", (char *) param);
  }
}

int main(int argc, char **argv) {
  foo(int, 5);
  foo(char *, "omg");

  return 0;
}