curl\_multi\_wakeup(3) Library Functions Manual curl\_multi\_wakeup(3)

# [NAME](#NAME)

curl\_multi\_wakeup - wake up a sleeping curl\_multi\_poll call

# [SYNOPSIS](#SYNOPSIS)

```
#include <curl/curl.h>
CURLMcode curl_multi_wakeup(CURLM *multi_handle);
```

# [DESCRIPTION](#DESCRIPTION)

This function can be called from any thread and it wakes up a sleeping [*curl\_multi\_poll(3)*](/man/os/curl/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)*](/man/os/curl/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)*](/man/os/curl/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)*](/man/os/curl/curl_multi_wait.3) calls.

# [PROTOCOLS](#PROTOCOLS)

This functionality affects all supported protocols

# [EXAMPLE](#EXAMPLE)

```
extern int time_to_die(void);
extern int set_something_to_signal_thread_1_to_exit(void);
extern int decide_to_stop_thread1(void);
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](#AVAILABILITY)

Added in curl 7.68.0

# [RETURN VALUE](#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)*](/man/os/curl/libcurl-errors.3).

# [SEE ALSO](#SEE_ALSO)

[**curl\_multi\_poll**(3)](/man/os/curl/curl_multi_poll.3), [**curl\_multi\_wait**(3)](/man/os/curl/curl_multi_wait.3)

2026-10-22 libcurl

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Document: curl_multi_wakeup(3) from curl 8.23.0-r2 (Chainguard OS)
Source: https://github.com/curl/curl.git