**************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 2018 - 2021, 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.
*
**************************************************************************

CURLOPT_DOH_URL - provide the DNS-over-HTTPS URL #include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_DOH_URL, char *URL); Pass in a pointer to a URL for the DoH server to use for name resolving. The parameter should be a char * to a null-terminated string which must be URL-encoded in the following format: "https://host:port/path". It MUST specify a HTTPS URL. libcurl does not validate the syntax or use this variable until the transfer is issued. Even if you set a crazy value here, curl_easy_setopt(3) will still return CURLE_OK. curl sends POST requests to the given DNS-over-HTTPS URL. To find the DoH server itself, which might be specified using a name, libcurl will use the default name lookup function. You can bootstrap that by providing the address for the DoH server with CURLOPT_RESOLVE(3). Disable DoH use again by setting this option to NULL. DoH lookups use SSL and some SSL settings from your transfer are inherited, like CURLOPT_SSL_CTX_FUNCTION(3). The hostname and peer certificate verification settings are not inherited but can be controlled separately via CURLOPT_DOH_SSL_VERIFYHOST(3) and CURLOPT_DOH_SSL_VERIFYPEER(3). A set CURLOPT_OPENSOCKETFUNCTION(3) callback is not inherited. NULL - there is no default DoH URL. If this option is not set, libcurl will use the default name resolver. All

CURL *curl = curl_easy_init();
if(curl) {
 curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
 curl_easy_setopt(curl, CURLOPT_DOH_URL, "https://dns.example.com");
 curl_easy_perform(curl);
}

Added in 7.62.0 Returns CURLE_OK on success or CURLE_OUT_OF_MEMORY if there was insufficient heap space. Note that curl_easy_setopt(3) will not actually parse the given string so given a bad DoH URL, curl will not detect a problem until it tries to resolve a name with it. CURLOPT_VERBOSE "(3), " CURLOPT_RESOLVE "(3), "