Do you realy want to use [ and ] as patern delimiters? My quess is that
you want to use it for defining character class. Then the only character
that must be escaped is -

'/[^a-z0-9,._+()\-]/i'

Luis Lebron wrote:
> 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
>