convert a string to integer

Hi, i know this topic is obvious but i have a strange behavior and i'm getting crazy. my stored procedure returns me a string. string can be an email or a message error => '-1', '-2', '-3' when i check if the string contains only digit, i use ctype_digit(mystring) but any way it returns me false... i suppose that for -1, -2, -3 the "-" is taken as character and not a digit. i tried also to cast it before into integer thanks ctype_digit((int)mystring), but it does not work. so how can i solve this issue ? thx -- Alain ------------------------------------ Windows XP SP2 PostgreSQL 8.2.4 / MS SQL server 2005 Apache 2.2.4 PHP 5.2.4 C# 2005-2008