Location regular expression explanation

Hi,

I was recently reading the PHPfastcgi example at
PHP FastCGI Example | NGINX. When it talks about the
configuration to avoid the exploit on uploads folder, there is a
regulare expresion saying: location ~*
(^(?!(?:(?!(php|inc)).)/blogs.dir/).?(php|inc)) {

I don’t understand that regular expresion. Could someone explain me what
?! ?: mean or send me some link to documentation about this?? I cannot
find anything after some googling.

Thanks and regards.

Posted at Nginx Forum:

On Fri, Aug 03, 2012 at 02:28:09AM -0400, diego_xa wrote:

find anything after some googling.

Thanks and regards.

http://www.pcre.org/pcre.txt