curl_multi_wakeup(3) Library Functions Manual curl_multi_wakeup(3)
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 mc;
int numfds;
mc = curl_multi_perform(multi, &still_running);
if(mc == CURLM_OK) {
/* wait for activity, timeout or wakeup */
mc = 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).
SEE ALSO
curl_multi_poll(3), curl_multi_wait(3)
libcurl 2026-07-12 curl_multi_wakeup(3)
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