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curl_multi_poll(3)		libcurl	Manual		    curl_multi_poll(3)

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

SYNOPSIS
       #include	<curl/curl.h>

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

DESCRIPTION
       curl_multi_poll(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.

       The curl_multi_wakeup(3)	function can be	used from  another  thread  to
       wake  up	 this  function	 and return faster. This is one	of the details
       that makes this function	different than curl_multi_wait(3) which	cannot
       be woken	up this	way.

       If  no  extra file descriptors are provided and libcurl has no file de-
       scriptor	to offer to wait for, this function will instead  wait	during
       timeout_ms milliseconds (or shorter if an internal timer	indicates so).
       This is the other  detail  that	makes  this  function  different  than
       curl_multi_wait(3).

       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	or timeout */
	   mc =	curl_multi_poll(multi_handle, NULL, 0, 1000, &numfds);
	 }

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

       } 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 7.66.0.

SEE ALSO
       curl_multi_fdset(3),	curl_multi_perform(3),	   curl_multi_wait(3),
       curl_multi_wakeup(3)

libcurl	7.72.0		       November	17, 2019	    curl_multi_poll(3)

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

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