**************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2020, 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.haxx.se/docs/copyright.html.
*
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* 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.
*
**************************************************************************

CURLINFO_OS_ERRNO - get errno number from last connect failure #include <curl/curl.h> CURLcode curl_easy_getinfo(CURL *handle, CURLINFO_OS_ERRNO, long *errnop); Pass a pointer to a long to receive the errno variable from a connect failure. Note that the value is only set on failure, it is not reset upon a successful operation. The number is OS and system specific. All

CURL *curl = curl_easy_init();
if(curl) {
 CURLcode res;
 curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
 res = curl_easy_perform(curl);
 if(res != CURLE_OK) {
 long error;
 res = curl_easy_getinfo(curl, CURLINFO_OS_ERRNO, &error);
 if(res && error) {
 printf("Errno: %ld\\n", error);
 }
 }
 curl_easy_cleanup(curl);
}

Added in 7.12.2 Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not. curl_easy_getinfo "(3), " curl_easy_setopt "(3), "