dladdr.c

#include <dlfcn.h>
#include <stdio.h>
#include <stdlib.h>

int main() {
  Dl_info info;
  int success = dladdr(main, &info);
  if (success == 0) abort();
  printf("main is at %p and the mach-o header that contains it is at %p\n", main, info.dli_fbase);
}