etc) are very accepting with their input arguments, you can pass any string to to them and they give a best effort of converting it. For example base_convert(“hello world”, 16, 10); will return 237 with no warnings. What this does internally is base_convert(“ed”, 16, 10); https://3v4l.org/3Jbem Also negative numbers simply do not work, eg base_convert(“-ff”, 16, 10); will return 255. (similar to above the “-” gets silently ignored). https://3v4l.org/nTaIL