/in/foo.c: In function 'next':
/in/foo.c:424:5: warning: 'main' is normally a non-static function [-Wmain]
  424 | int main() {
      |     ^~~~
/in/foo.c:427:1: error: expected declaration or statement at end of input
  427 | }
      | ^
/in/foo.c: At top level:
/in/foo.c:424:5: warning: 'main' defined but not used [-Wunused-function]
  424 | int main() {
      |     ^~~~
/in/foo.c:297:6: warning: 'next_op' defined but not used [-Wunused-function]
  297 | void next_op() {
      |      ^~~~~~~