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CURLOPT_RESOLVER_START_FUNCcurl_easy_setopt CURLOPT_RESOLVER_START_FUNCTION(3)

NAME
       CURLOPT_RESOLVER_START_FUNCTION	-  set	callback to be called before a
       new resolve request is started

SYNOPSIS
       #include	<curl/curl.h>

       int resolver_start_cb(void *resolver_state, void	*reserved, void	*userdata);

       CURLcode	curl_easy_setopt(CURL *handle,
				 CURLOPT_RESOLVER_START_FUNCTION,
				 resolver_start_cb);

DESCRIPTION
       Pass a pointer to your callback function, which should match the	proto-
       type shown above.

       This  callback  function	gets called by libcurl every time before a new
       resolve request is started.

       resolver_state points to	a backend-specific resolver  state.  Currently
       only  the ares resolver backend has a resolver state. It	can be used to
       set up any desired option on the	ares channel before it's used, for ex-
       ample setting up	socket callback	options.

       reserved	is reserved.

       userdata	   is	 the   user   pointer	set   with   the   CURLOPT_RE-
       SOLVER_START_DATA(3) option.

       The callback must return	0 on success. Returning	a non-zero value  will
       cause the resolve to fail.

DEFAULT
       NULL (No	callback)

PROTOCOLS
       All

EXAMPLE
       static int resolver_start_cb(void *resolver_state, void *reserved,
				    void *userdata)
       {
	 (void)reserved;
	 printf("Received resolver_state=%p userdata=%p\n",
		resolver_state,	userdata);
	 return	0;
       }

       CURL *curl = curl_easy_init();
       if(curl)	{
	 curl_easy_setopt(curl,	CURLOPT_RESOLVER_START_FUNCTION, resolver_start_cb);
	 curl_easy_setopt(curl,	CURLOPT_RESOLVER_START_DATA, curl);
	 curl_easy_setopt(curl,	CURLOPT_URL, "http://example.com");
	 curl_easy_perform(curl);
	 curl_easy_cleanup(curl);
       }

AVAILABILITY
       Added in	7.59.0

RETURN VALUE
       Returns CURLE_OK

SEE ALSO
       CURLOPT_RESOLVER_START_DATA(3)

libcurl	7.72.0		       February	14, CURLOPT_RESOLVER_START_FUNCTION(3)

NAME | SYNOPSIS | DESCRIPTION | DEFAULT | PROTOCOLS | EXAMPLE | AVAILABILITY | RETURN VALUE | SEE ALSO

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