www.LinuxHowtos.org

curl_multi_wakeup

Section: C Library Functions (3)
Updated: 202-0-19
Index Return to Main Contents

NAME

curl_multi_wakeup - wake up a sleeping curl_multi_poll call

SYNOPSIS

#include <curl/curl.h>

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 is about to be) waiting for activity or a timeout.

If the function is called when there is no curl_multi_poll(3) call, it causes 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 wake up the same waiting operation.

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

PROTOCOLS

This functionality affects all supported protocols

EXAMPLE

extern int time_to_die(void);
extern int set_something_to_signal_thread_1_to_exit(void);
extern int decide_to_stop_thread1();

int main(void)
{
  CURL *easy;
  CURLM *multi = curl_multi_init();
  int still_running;

  easy = curl_easy_init();

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

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

    mresult = curl_multi_perform(multi, &still_running);

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

    if(time_to_die())
      return 1;

  } while(still_running);

  curl_multi_remove_handle(multi, easy);

  /* this is thread 2 */

  if(decide_to_stop_thread1()) {

    set_something_to_signal_thread_1_to_exit();

    curl_multi_wakeup(multi);
  }
}

AVAILABILITY

Added in curl 7.68.0

RETURN VALUE

This function returns a CURLMcode indicating success or error.

CURLM_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3).