~ $ cat sizeofmacro.c
  #include <stdio.h>

  #define pintsize(T) printf("sizeof(%s) is %zu. Big or small? You decide.\n", #T, sizeof(T))

  int main(int argc, char **argv) {
          pintsize(int);
          pintsize(argv);
          return 0;
  }
  ~ $ gcc sizeofmacro.c && ./a.out
  sizeof(int) is 4. Big or small? You decide.
  sizeof(argv) is 8. Big or small? You decide.