Sorry, but this strays a little from actual boost. Since there are a handful of you that are probably using regex, I was hoping someone could help with syntax. I have a regex that validates a latitude format. These are the restrictions: Must have an N or S as first letter. It can be all values from 0.0 to 90.0 My first shot at it confirmed format, but not data constraints: "(N|S)\\d{2}\\.\\d{1,6} file:///\\d%7b2%7d\d%7b1,6%7d " But any attempts to limit the constraints caused an exception in regex. Is there something wrong w/ how I formatted this: "(N|S)(9[0]\\.0{1-6}|[0-8]\\d\\.\\d{1-6} file:///\\.0%7b1-6%7d|[0-8]\d\d%7b1-6%7d )" To me, it reads: 1st char must be N|S If second char is 9, the next chars must be 0.0 through 0.000000 Else If char is 0-8, then the next just has to be digits [0-9].[0-9]{1-6} Can anyone tell me what I am doing wrong? Just FYI, I am coding in VS 2005 C++ Thanks