curl_multi_info_read(3) [osx man page]

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 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 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  calling  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 information.  If more involved information is wanted, the particular "easy
       handle" in present in that struct and can thus 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.

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 7.10.3							    18 Dec 2004 					   curl_multi_info_read(3)

curl_multi_perform(3)						  libcurl Manual					     curl_multi_perform(3)

NAME

       curl_multi_perform - reads/writes available data from each easy handle

SYNOPSIS

       #include <curl/curl.h>

       CURLMcode curl_multi_perform(CURLM *multi_handle, int *running_handles);

DESCRIPTION

       When  the  app  thinks there's data available for the multi_handle, it should call this function to read/write whatever there is to read or
       write right now. curl_multi_perform() returns as soon as the reads/writes are done. This function does not require that there  actually	is
       any  data  available for reading or that data can be written, it can be called just in case. It will write the number of handles that still
       transfer data in the second argument's integer-pointer.

       When you call curl_multi_perform() and the amount of running_handles is changed from the previous call (or is less than the amount of  easy
       handles	you've	added  to  the	multi  handle),  you  know  that  there  is  one  or  more  transfers  less  "running".  You can then call
       curl_multi_info_read(3) to get information about each individual completed transfer, and that returned info includes CURLcode and more.	If
       an added handle fails very quickly, it may never be counted as a running_handle.

       When running_handles is set to zero (0) on the return of this function, there is no longer any transfers in progress.

RETURN VALUE

       CURLMcode type, general libcurl multi interface error code.

       Before  version 7.20.0: If you receive CURLM_CALL_MULTI_PERFORM, this basically means that you should call curl_multi_perform again, before
       you select() on more actions. You don't have to do it immediately, but the return code means that libcurl may have more data  available	to
       return  or  that  there	may  be  more  data  to  send  off  before  it	is  "satisfied".  Do  note  that curl_multi_perform(3) will return
       CURLM_CALL_MULTI_PERFORM only when it wants to be called again immediately. When things are fine and there is nothing  immediate  it  wants
       done, it'll return CURLM_OK and you need to wait for "action" and then call this function again.

       This  function  only  returns  errors etc regarding the whole multi stack.  Problems still might have occurred on individual transfers even
       when this function returns CURLM_OK.

TYPICAL USAGE

       Most applications will use curl_multi_fdset(3) to get the multi_handle's file descriptors,  then  it'll	wait  for  action  on  them  using
       select(3) and as soon as one or more of them are ready, curl_multi_perform(3) gets called.

SEE ALSO

       curl_multi_cleanup(3), curl_multi_init(3), curl_multi_fdset(3), curl_multi_info_read(3), libcurl-errors(3)

libcurl 7.9.5							   1 March 2002 					     curl_multi_perform(3)