Check whether the string is a unix timestamp

Question

I have a string and I need to find out whether it is a unix timestamp or not, how can I do that effectively?

I found this thread via Google, but it doesn\'t come up

Answer 1

If you might think to replace this solution with is_numeric(), please consider that php native function provides false positives for input strings like "1.1", "0123", "0xFF" which are not in timestamp format.