NAME

       curl_multi_info_read - read multi stack information

SYNOPSIS

       #include <curl/curl.h>

       CURLMsg *curl_multi_info_read(CURLM *multi_handle, int *msgs_in_queue);

DESCRIPTION

       Ask the multi handle if there are any messages from the individual transfers. Messages may
       include information such as an error code from the  transfer  or  just  the  fact  that  a
       transfer is completed. More details on these should be written down as well.

       Repeated  calls  to this function returns a new struct each time, until a NULL is returned
       as a signal that there is no more to get at  this  point.  The  integer  pointed  to  with
       msgs_in_queue contains the number of remaining messages after this function was called.

       When  you  fetch  a  message using this function, it is removed from the internal queue so
       calling this function again does not return the same message again. It instead returns new
       messages at each new invoke until the queue is emptied.

       WARNING:   The   data   the   returned   pointer   points  to  does  not  survive  calling
       curl_multi_cleanup(3), curl_multi_remove_handle(3) or curl_easy_cleanup(3).

       The CURLMsg struct is simple  and  only  contains  basic  information.  If  more  involved
       information  is  wanted, the particular "easy handle" is present in that struct and can be
       used in subsequent regular curl_easy_getinfo(3) calls (or similar):

        struct CURLMsg {
          CURLMSG msg;       /* what this message means */
          CURL *easy_handle; /* the handle it concerns */
          union {
            void *whatever;    /* message-specific data */
            CURLcode result;   /* return code for transfer */
          } data;
        };

       When msg is CURLMSG_DONE, the message identifies a transfer that is done, and then  result
       contains the return code for the easy handle that just completed.

       At this point, there are no other msg types defined.

PROTOCOLS

       This functionality affects all supported protocols

EXAMPLE

       int main(void)
       {
         CURLM *multi = curl_multi_init();
         CURL *curl = curl_easy_init();
         if(curl) {
           struct CURLMsg *m;

           /* call curl_multi_perform or curl_multi_socket_action first, then loop
              through and check if there are any transfers that have completed */

           do {
             int msgq = 0;
             m = curl_multi_info_read(multi, &msgq);
             if(m && (m->msg == CURLMSG_DONE)) {
               CURL *e = m->easy_handle;
               /* m->data.result holds the error code for the transfer */
               curl_multi_remove_handle(multi, e);
               curl_easy_cleanup(e);
             }
           } while(m);
         }
       }

AVAILABILITY

       Added in curl 7.9.6

RETURN VALUE

       A  pointer  to  a  filled-in  struct,  or NULL if it failed or ran out of structs. It also
       writes the number of messages left in the queue (after  this  read)  in  the  integer  the
       second argument points to.

SEE ALSO

       curl_multi_cleanup(3), curl_multi_init(3), curl_multi_perform(3)