#PHP, 15 bytes, 2 exit codes
PHP, 15 bytes, 2 exit codes
Without die/exit, PHP cannot return anything but 0 or 255 (afaik; probably ~1), so ...
!$argv[1]?:p(); If command line argument is falsy, it evaluates to 1 and exits with 0. If not, it tries to call a function and exits with <b>Fatal error</b>: Uncaught Error: Call to undefined function p().
Run with -r.