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


       curl_multi_info_read - read multi stack information


       #include <curl/curl.h>

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


       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  will  return  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  will contain the number of remaining messages after this function was

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

       WARNING:  The  data  the  returned  pointer   points   to   will   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.


       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_handle, &msgq);
         if(m && (m->msg == CURLMSG_DONE)) {
           CURL *e = m->easy_handle;
           curl_multi_remove_handle(multi_handle, e);
       } while(m);


       Added in 7.9.6


       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.


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