87 lines
2.9 KiB
Groff
87 lines
2.9 KiB
Groff
.\" **************************************************************************
|
|
.\" * _ _ ____ _
|
|
.\" * Project ___| | | | _ \| |
|
|
.\" * / __| | | | |_) | |
|
|
.\" * | (__| |_| | _ <| |___
|
|
.\" * \___|\___/|_| \_\_____|
|
|
.\" *
|
|
.\" * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
|
|
.\" *
|
|
.\" * This software is licensed as described in the file COPYING, which
|
|
.\" * you should have received as part of this distribution. The terms
|
|
.\" * are also available at https://curl.se/docs/copyright.html.
|
|
.\" *
|
|
.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
|
|
.\" * copies of the Software, and permit persons to whom the Software is
|
|
.\" * furnished to do so, under the terms of the COPYING file.
|
|
.\" *
|
|
.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
|
|
.\" * KIND, either express or implied.
|
|
.\" *
|
|
.\" * SPDX-License-Identifier: curl
|
|
.\" *
|
|
.\" **************************************************************************
|
|
.\"
|
|
.TH CURLOPT_RESOLVER_START_FUNCTION 3 "14 Feb 2018" libcurl libcurl
|
|
.SH NAME
|
|
CURLOPT_RESOLVER_START_FUNCTION \- callback called before a new name resolve is started
|
|
.SH SYNOPSIS
|
|
.nf
|
|
#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);
|
|
.SH DESCRIPTION
|
|
Pass a pointer to your callback function, which should match the prototype
|
|
shown above.
|
|
|
|
This callback function gets called by libcurl every time before a new resolve
|
|
request is started.
|
|
|
|
\fIresolver_state\fP 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 example setting up
|
|
socket callback options.
|
|
|
|
\fIreserved\fP is reserved.
|
|
|
|
\fIuserdata\fP is the user pointer set with the
|
|
\fICURLOPT_RESOLVER_START_DATA(3)\fP option.
|
|
|
|
The callback must return 0 on success. Returning a non-zero value causes the
|
|
resolve to fail.
|
|
.SH DEFAULT
|
|
NULL (No callback)
|
|
.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, "https://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_PREREQFUNCTION (3),
|
|
.BR CURLOPT_RESOLVER_START_DATA (3)
|