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Problem where timer callback keeps setting a 0 timer

From: Jeff Mears via curl-library <curl-library_at_cool.haxx.se>
Date: Wed, 4 Dec 2019 04:33:36 +0000

I have a background thread that starts and stops libcurl downloads using the "multi" interface. It has a poll() loop that waits for something to happen on either one of libcurl's sockets or on a loopback socket that is used to interrupt poll().

After running for a bit, there is a periodic HTTP request we send. When these start, libcurl calls our CURLMOPT_TIMERFUNCTION with a timeout of 0. So the poll() loop starts polling with hot CPU.

The download then completes. We curl_multi_remove_handle() then curl_easy_cleanup() in our handling of the curl_multi_info_read() messages.

However, at this point, even though libcurl has no active downloads on the multi handle, we never get a timer callback to set the timeout back to -1, so our poll() loop continues running hot.

Am I doing something wrong? For now, I'm going to set the timeout to -1 when curl_multi_socket_action(CURL_SOCKET_TIMEOUT) returns 0 running handles to stop the thread running hot.

Thanks!

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Received on 2019-12-04