Security Basics: Help with C/C++ socket programming

["Siddharth Upmanyu" <siddharth () techbugs org>]

Hi,
I was trying to write a simple http client and it is working fine on
direct connection (like connecting to google.com on port 80 and
downloading the html to a file)

the problem is I want to make it run on http proxy which is set in my
default browser, how can i findout this proxy ip/port from my c
code...
it shouldnt matter whatever browser it is (i can use IE specific
registry values but this wont work on other browsers...)

Thanks in advance,

Regards
Siddharth