[PHP] preg match compilation error

[Luis Lebron]

I found a reqular expresion that I'm using to check for valid characters in
file names.

Here's the sample code:

if(preg_match("[^a-zA-Z0-9,._\+\()\-]",$filename))
{
        //blah, blah, blah
}

However, when I run the script I get the following error:
Warning: Compilation failed: unmatched parentheses at offset 17 in
/home/httpd/sigmarapid/html/test/upload.php on line 137 (the line with the
preg_match)

I'm new to regular expressions so any help would be greatly appreciated.

Luis R. Lebron
Sigmatech, Inc