src/DateTime.php
public static function isTimestamp($timestamp)
    {
        if (is_bool($timestamp) || !is_scalar($timestamp)) {
            return false;
        }
        return ((string)(int)$timestamp === (string)$timestamp)
        && ($timestamp <= PHP_INT_MAX)
        && ($timestamp >= ~PHP_INT_MAX);
    }
public static function isTimestamp($timestamp)
    {
        if (is_bool($timestamp) || !is_scalar($timestamp)) {
            return false;
        }
        return ((string)(int)$timestamp === (string)$timestamp)
        && ($timestamp <= PHP_INT_MAX)
        && ($timestamp >= ~PHP_INT_MAX);
    }
public static function isTimestamp ( $ timestamp ) { if ( is_bool ( $ timestamp ) || ! is_scalar ( $ timestamp ) ) { return false ; } return ( ( string ) ( int ) $ timestamp === ( string ) $ timestamp ) && ( $ timestamp <= PHP_INT_MAX ) && ( $ timestamp >= ~ PHP_INT_MAX ) ; }
Validate is timestamp.

@param string|int $timestamp
@return bool
Validate is timestamp .