CURLMOPT_TIMERFUNCTION(3)

CURLMOPT_TIMERFUNCTION(3curl_multi_setopt optionCURLMOPT_TIMERFUNCTION(3)

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) {

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CURLMOPT_TIMERFUNCTION(3curl_multi_setopt optionCURLMOPT_TIMERFUNCTION(3)

         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),

libcurl 7.58.0      Last change: May 27, 2017                   2