Provided by: libcurl4-doc_7.58.0-2ubuntu3_all bug

NAME

       CURLMOPT_TIMERFUNCTION - set callback to receive timeout values

SYNOPSIS

       #include <curl/curl.h>

       int timer_callback(CURLM *multi,    /* multi handle */
                          long timeout_ms, /* see above */
                          void *userp);    /* private callback pointer */

       CURLMcode curl_multi_setopt(CURLM *handle, CURLMOPT_TIMERFUNCTION, timer_callback);

DESCRIPTION

       Pass a pointer to your callback function, which should match the prototype shown above.

       Certain  features,  such  as  timeouts  and retries, require you to call libcurl even when
       there is no activity on the file descriptors.

       Your callback function  timer_callback  should  install  a  non-repeating  timer  with  an
       interval    of    timeout_ms.    Each    time    that    timer    fires,    call    either
       curl_multi_socket_action(3) or curl_multi_perform(3), depending  on  which  interface  you
       use.

       A timeout_ms value of -1 means you should delete your timer.

       A   timeout_ms   value   of   0  means  you  should  call  curl_multi_socket_action(3)  or
       curl_multi_perform(3) (once) as soon as possible.

       timer_callback will only be called when the timeout_ms changes.

       The userp pointer is set with CURLMOPT_TIMERDATA(3).

       The timer callback should return 0 on success, and -1 on error. This callback can be  used
       instead of, or in addition to, curl_multi_timeout(3).

DEFAULT

       NULL

PROTOCOLS

       All

EXAMPLE

       static gboolean timeout_cb(gpointer user_data)
       {
         int running;
         if(user_data) {
           g_free(user_data);
           curl_multi_setopt(curl_handle, CURLMOPT_TIMERDATA, NULL);
         }
         curl_multi_socket_action(multi, CURL_SOCKET_TIMEOUT, 0, &running);
         return G_SOURCE_REMOVE;
       }

       static int timerfunc(CURLM *multi, long timeout_ms, void *userp)
       {
         guint *id = userp;

         if(id)
           g_source_remove(*id);

         /* -1 means we should just delete our timer. */
         if(timeout_ms == -1) {
           g_free(id);
           id = NULL;
         }
         else {
           if(!id)
             id = g_new(guint, 1);
           *id = g_timeout_add(timeout_ms, timeout_cb, id);
         }
         curl_multi_setopt(multi, CURLMOPT_TIMERDATA, id);
         return 0;
       }

       curl_multi_setopt(multi, CURLMOPT_TIMERFUNCTION, timerfunc);

AVAILABILITY

       Added in 7.16.0

RETURN VALUE

       Returns CURLM_OK if the option is supported, and CURLM_UNKNOWN_OPTION if not.

SEE ALSO

       CURLMOPT_TIMERDATA(3), CURLMOPT_SOCKETFUNCTION(3),