docs/libcurl/opts/CURLOPT_RESOLVER_START_DATA.3

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  23 .TH CURLOPT_RESOLVER_START_DATA 3 "February 14, 2018" "libcurl 7.59.0" "curl_easy_setopt options"
  24
  25 .SH NAME
  26 CURLOPT_RESOLVER_START_DATA \- custom pointer passed to the resolver start callback
  27 .SH SYNOPSIS
  28 #include <curl/curl.h>
  29
  30 CURLcode curl_easy_setopt(CURL *handle, CURLOPT_RESOLVER_START_DATA, void *pointer);
  31 .SH DESCRIPTION
  32 Pass a \fIpointer\fP that will be untouched by libcurl and passed as the third
  33 argument in the resolver start callback set with
  34 \fICURLOPT_RESOLVER_START_FUNCTION(3)\fP.
  35 .SH DEFAULT
  36 NULL
  37 .SH PROTOCOLS
  38 All
  39 .SH EXAMPLE
  40 .nf
  41 static int resolver_start_cb(void *resolver_state, void *reserved,
  42                              void *userdata)
  43 {
  44   (void)reserved;
  45   printf("Received resolver_state=%p userdata=%p\\n",
  46          resolver_state, userdata);
  47   return 0;
  48 }
  49
  50 CURL *curl = curl_easy_init();
  51 if(curl) {
  52   curl_easy_setopt(curl, CURLOPT_RESOLVER_START_FUNCTION, resolver_start_cb);
  53   curl_easy_setopt(curl, CURLOPT_RESOLVER_START_DATA, curl);
  54   curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");
  55   curl_easy_perform(curl);
  56   curl_easy_cleanup(curl);
  57 }
  58 .fi
  59 .SH AVAILABILITY
  60 Added in 7.59.0
  61 .SH RETURN VALUE
  62 Returns CURLE_OK
  63 .SH "SEE ALSO"
  64 .BR CURLOPT_RESOLVER_START_FUNCTION "(3) "