curl_multi_wakeup

Section: libcurl Manual (3)
Updated: November 05, 2020
Page Index

NAME

curl_multi_wakeup - wakes up a sleeping curl_multi_poll call

SYNOPSIS

CURLMcode curl_multi_wakeup(CURLM *multi_handle);

DESCRIPTION

This function can be called from any thread and it wakes up a sleeping curl_multi_poll(3) call that is currently (or will be) waiting for activity or a timeout.

If the function is called when there is no curl_multi_poll(3) call, it will cause the next call to return immediately.

Calling this function only guarantees to wake up the current (or the next if there is no current) curl_multi_poll(3) call, which means it is possible that multiple calls to this function will wake up the same waiting operation.

This function has no effect on curl_multi_wait(3) calls.

RETURN VALUE

CURLMcode type, general libcurl multi interface error code.

AVAILABILITY

Added in 7.68.0

EXAMPLE

CURL *easy_handle;
CURLM *multi_handle;

/* add the individual easy handle */
curl_multi_add_handle(multi_handle, easy_handle);

/* this is thread 1 */
do {
  CURLMcode mc;
  int numfds;

  mc = curl_multi_perform(multi_handle, &still_running);

  if(mc == CURLM_OK) {
    /* wait for activity, timeout or wakeup */
    mc = curl_multi_poll(multi_handle, NULL, 0, 10000, &numfds);
  }

  if(time_to_die())
    exit(1);

} while(still_running);

curl_multi_remove_handle(multi_handle, easy_handle);

/* this is thread 2 */

if(something makes us decide to stop thread 1) {

  set_something_to_signal_thread_1_to_exit();

  curl_multi_wakeup(multi_handle);
}