To disable output buffering put

$|=1;
[download]

See also perlvar.

With some older web servers, you'll also need to designate the CGI as being nph (non-parsed headers), so that the webserver doesn't buffer the output:

• http://httpd.apache.org/docs/misc/FAQ-F.html#nph-scripts
• http://faq.perl.org/perlfaq9.html#What_is_the_correct_

++Joost, I can't believe I just stumbled across this at exactly the right time.

I have never had this problem, but just switch to Pair Networks and all my Perl/CGI/HTML::Template page loads were taking forever. My customers were not happy. So, I added the $|=1 to the start of all my scripts and magic! Problem solved. Thanks.


—Brad
"The important work of moving the world forward does not wait to be done by perfect men." George Eliot

An alternate if you have some long processing that can continue without any further feedback to the user after sending "Thanks for your submission" is to fork a process to the long processing and close all of the STDIO handles in that process - in that way the main process will end and the server close the connection to the browser but you can continue processing:

#!/usr/bin/perl -w
                                                                      
+          
use CGI qw(:standard);
                                                                      
+          
local $| = 1;
                                                                      
+          
print header("text/plain"), "this is a test";
                                                                      
+          
if (!fork )
{
   close STDOUT;
   close STDIN;
   close STDERR;
                                                                      
+          
   # some long running processing ...

   for ( 1 ... 1000 )
   {
      sleep 1;
   }
}
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/J\

That's the really old way. You probably want to look at the newer way, instead.

-- Randal L. Schwartz, Perl hacker
Be sure to read my standard disclaimer if this is a reply.

I understood your problem, usually in web based or browser based projects and
if it takes some time to load page(includes backend processing), it is designed to show some graphics work(ex. progress bar) indicating the processing. It makes the user to feel that process is going on.

And user also can avoid seeing dirty stuffs displayed, half processed.
I think this make sense and this idea is used in major web sites(ex: yahoo while file upload)