Provided by: libcurl4-doc_7.88.1-8ubuntu1_all bug


       curl_multi_poll - polls on all easy handles in a multi handle


       #include <curl/curl.h>

       CURLMcode curl_multi_poll(CURLM *multi_handle,
                                 struct curl_waitfd extra_fds[],
                                 unsigned int extra_nfds,
                                 int timeout_ms,
                                 int *numfds);


       curl_multi_poll(3)  polls  all file descriptors used by the curl easy handles contained in
       the given multi handle set. It will block until activity is detected on at  least  one  of
       the  handles  or  timeout_ms has passed.  Alternatively, if the multi handle has a pending
       internal timeout that has a shorter expiry time than timeout_ms, that shorter time will be
       used instead to make sure timeout accuracy is reasonably kept.

       The  calling  application  may pass additional curl_waitfd structures which are similar to
       poll(2)'s pollfd structure to be waited on in the same call.

       On completion, if numfds is non-NULL, it will be populated with the total number  of  file
       descriptors  on  which  interesting  events occurred. This number can include both libcurl
       internal descriptors as well as descriptors provided in extra_fds.

       The curl_multi_wakeup(3) function can be used from another thread to wake up this function
       and  return  faster.  This  is  one of the details that makes this function different than
       curl_multi_wait(3) which cannot be woken up this way.

       If no extra file descriptors are provided and libcurl has no file descriptor to  offer  to
       wait for, this function will instead wait during timeout_ms milliseconds (or shorter if an
       internal timer indicates so). This is the other detail that makes this function  different
       than curl_multi_wait(3).

       This function is encouraged to be used instead of select(3) when using the multi interface
       to allow applications to easier circumvent the  common  problem  with  1024  maximum  file


       struct curl_waitfd {
         curl_socket_t fd;
         short events;
         short revents;

              Bit  flag  to  indicating the socket should poll on read events
              such as new data received.

              Bit flag to indicating the socket should poll on  high  priority
              read events such as out of band data.

              Bit  flag  to indicating the socket should poll on write events
              such as the socket being clear to write without blocking.


       CURL *easy_handle;
       CURLM *multi_handle;

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

       do {
         CURLMcode mc;
         int numfds;

         mc = curl_multi_perform(multi_handle, &still_running);

         if(mc == CURLM_OK) {
           /* wait for activity or timeout */
           mc = curl_multi_poll(multi_handle, NULL, 0, 1000, &numfds);

         if(mc != CURLM_OK) {
           fprintf(stderr, "curl_multi failed, code %d.\n", mc);

       } while(still_running);

       curl_multi_remove_handle(multi_handle, easy_handle);


       Added in 7.66.0.


       CURLMcode type, general libcurl multi interface error code. See libcurl-errors(3)


       curl_multi_fdset(3), curl_multi_perform(3), curl_multi_wait(3), curl_multi_wakeup(3)