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

Improved answer to @TD_Nijboer.

This will avoid an exception be thrown if the supplied string is not a time stamp:

function isTimestamp($timestamp) {
    if(ctype_digit($timestamp) && strtotime(date('Y-m-d H:i:s',$timestamp)) === (int)$timestamp) {
        return true;
    } else {
        return false;
    }
}