curl_multi_exec failed with error code 0

There is a call to curl_multi_exec in function purge_issue_requests_curl($purges) in purge.inc file. It fails with curl error code 0 and http error code 0. This is the code

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// Execute the purge requests
ob_start();
do {
$mrc = curl_multi_exec($curl_purges, $active);
} while ($mrc == CURLM_CALL_MULTI_PERFORM);
ob_end_clean();
**********************************
I think the problem is that the php script dies prematurely without allowing enough time for curl_multi_exec function to complete
I was able to fix the problem by adding following code to introduce some waiting period

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// Execute the purge requests
ob_start();
do {
$mrc = curl_multi_exec($curl_purges, $active);
} while ($mrc == CURLM_CALL_MULTI_PERFORM);
// new code starts
while ($active && $mrc == CURLM_OK) {
if (curl_multi_select($curl_purges) != -1) {
do {
$mrc = curl_multi_exec($curl_purges, $active);
} while ($mrc == CURLM_CALL_MULTI_PERFORM);
}
}
//new code ends
ob_end_clean();
***********************************

Above code snippet for curl wait period is copied from php.net documentation for curl_multi_exec
http://www.php.net/manual/en/function.curl-multi-exec.php# (see first example)

I can work on this if required.