I've got a CGI script which does some lengthy processing and reports the results to the user. Right now I'm doing something like this: 

 #===== Open I/O pipes and run the process
  $pid = open3(\*DEV_NULL, \*OUT, \*ERR, "$my_long_process");
  
  #===== Print the results
  while (<OUT>)
  {
    $buffer .= "$_<br>";
  
    #===== Update the display cache
    $cache->set($session, [0, $buffer]);
  }

[download]

Which works, except it waits until $my_long_process completes before it sends any output back to the browser. If my_long_process takes an hour to run, the browser sits there for an hour with no updated information.

If I run my_long_process from the command line, however, it updates as it goes, so that the user knows what's going on.

Is there a way to set open3() to an unbuffered mode so it returns what my_long_process is doing in real time instead of waiting until the end?

Failing that, is there a better way to do this long process in the fork such that I can get its results as its doing things rather than waiting until the end?

Thanks!

CT

Charles Thomas
Madison, WI

In reply to Long Process Waits Until End to Display Results by C_T

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