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curl_multi_info_read(3)		libcurl	Manual	       curl_multi_info_read(3)

NAME
       curl_multi_info_read - read multi stack informationals

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/informationals from the
       individual transfers. Messages may include informationals  such	as  an
       error  code  from the transfer or just the fact that a transfer is com-
       pleted. More details on these should be written down as well.

       Repeated	calls to this function will return a new struct	each time, un-
       til 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  num-
       ber 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 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 call-
       ing	curl_multi_cleanup(3),	    curl_multi_remove_handle(3)	    or
       curl_easy_cleanup(3).

       The 'CURLMsg' struct is very simple and only contains very basic	infor-
       mation.	 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.

EXAMPLE
       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;
	   transfers--;
	   curl_multi_remove_handle(multi_handle, e);
	   curl_easy_cleanup(e);
	 }
       } while(m);

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)

libcurl	7.72.0			March 23, 2020	       curl_multi_info_read(3)

NAME | SYNOPSIS | DESCRIPTION | EXAMPLE | RETURN VALUE | SEE ALSO

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