curl/docs/libcurl/opts/CURLOPT_RESOLVER_START_DATA.3
Francisco Sedano 23713645d4 url: Add option CURLOPT_RESOLVER_START_FUNCTION
- Add new option CURLOPT_RESOLVER_START_FUNCTION to set a callback that
  will be called every time before a new resolve request is started
  (ie before a host is resolved) with a pointer to backend-specific
  resolver data. Currently this is only useful for ares.

- Add new option CURLOPT_RESOLVER_START_DATA to set a user pointer to
  pass to the resolver start callback.

Closes https://github.com/curl/curl/pull/2311
2018-02-21 21:29:10 -05:00

64 lines
2.2 KiB
Groff

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.TH CURLOPT_RESOLVER_START_DATA 3 "14 Feb 2018" "libcurl 7.59.0" "curl_easy_setopt options"
.SH NAME
CURLOPT_RESOLVER_START_DATA \- custom pointer passed to the resolver start callback
.SH SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_RESOLVER_START_DATA, void *pointer);
.SH DESCRIPTION
Pass a \fIpointer\fP that will be untouched by libcurl and passed as the third
argument in the resolver start callback set with
\fICURLOPT_RESOLVER_START_FUNCTION(3)\fP.
.SH DEFAULT
NULL
.SH PROTOCOLS
All
.SH EXAMPLE
.nf
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);
}
.fi
.SH AVAILABILITY
Added in 7.59.0
.SH RETURN VALUE
Returns CURLE_OK
.SH "SEE ALSO"
.BR CURLOPT_RESOLVER_START_FUNCTION "(3) "