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curl_multi_wait(3)		libcurl	Manual		    curl_multi_wait(3)

NAME
       curl_multi_wait - polls on all easy handles in a	multi handle

SYNOPSIS
       #include	<curl/curl.h>

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

DESCRIPTION
       curl_multi_wait(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 to-
       tal 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.

       If no extra file	descriptors are	provided and libcurl has no  file  de-
       scriptor	to offer to wait for, this function will return	immediately.

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

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

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

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

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

EXAMPLE
       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, timeout or "nothing" */
	   mc =	curl_multi_wait(multi_handle, NULL, 0, 1000, &numfds);
	 }

	 if(mc != CURLM_OK) {
	   fprintf(stderr, "curl_multi failed, code %d.0, mc);
	   break;
	 }

	 /* 'numfds' being zero	means either a timeout or no file descriptors to
	    wait for. Try timeout on first occurrence, then assume no file
	    descriptors	and no file descriptors	to wait	for means wait for 100
	    milliseconds. */

	 if(!numfds) {
	   repeats++; /* count number of repeated zero numfds */
	   if(repeats >	1) {
	     WAITMS(100); /* sleep 100 milliseconds */
	   }
	 }
	 else
	   repeats = 0;

       } while(still_running);

       curl_multi_remove_handle(multi_handle, easy_handle);

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

AVAILABILITY
       This function was added in libcurl 7.28.0.

SEE ALSO
       curl_multi_fdset(3), curl_multi_perform(3)

libcurl	7.54.1			March 09, 2016		    curl_multi_wait(3)

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

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