PHP communicates with the flex through AMF, my little brother I debug found that as long as there is a date () function, Flex returns an error

PHP communicates with Flex through AMF, and I debug the discovery that, as long as there is a date () function, Flex returns an error
a.php

 
 Class Edit_img
{
   function Gmtime ()
   {
    $temp = Date (' Z ');
    return $temp;
   }

}
?>
This PHP communicates with the flex through AMF, and I debug to find out that as long as there is a date () function, Flex returns with an error.

AMF is the 2.1.1 version, I can't think of this problem again and again

a.php

 
 Class Edit_img
{
   function Gmtime ()
   {
    $temp = time (); This is normal.
    return $temp;
   }

}
?>

------Solution--------------------
It is estimated that there is no time zone specified, resulting in the use of the date () function warning.
Block warning errors in PHP, or add Date_default_timezone_set ("Asia/shanghai") to PHP;

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