Question

i’m reading the source code of http-parser and came across some if statements with empty blocks. here’s an example (source)

int
dontcall_message_begin_cb (http_parser *p)
{
  if (p) { } // gcc
  fprintf(stderr, "\n\n*** on_message_begin() called on paused parser ***\n\n");
  abort();
}

the comment merely mentions ‘gcc’ which (to me) is not very helpful. what is the point of these?

Answer 1

My guess is someone trying to suppress the “unused parameter” warning.

The canonical way to do this is (void)p;, but I’m guessing the author of the code didn’t know about that.