xref: /third_party/curl/docs/examples/smtp-vrfy.c (revision 13498266)
1/***************************************************************************
2 *                                  _   _ ____  _
3 *  Project                     ___| | | |  _ \| |
4 *                             / __| | | | |_) | |
5 *                            | (__| |_| |  _ <| |___
6 *                             \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
9 *
10 * This software is licensed as described in the file COPYING, which
11 * you should have received as part of this distribution. The terms
12 * are also available at https://curl.se/docs/copyright.html.
13 *
14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15 * copies of the Software, and permit persons to whom the Software is
16 * furnished to do so, under the terms of the COPYING file.
17 *
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
20 *
21 * SPDX-License-Identifier: curl
22 *
23 ***************************************************************************/
24
25/* <DESC>
26 * Verify an SMTP email address
27 * </DESC>
28 */
29
30#include <stdio.h>
31#include <string.h>
32#include <curl/curl.h>
33
34/* This is a simple example showing how to verify an email address from an
35 * SMTP server.
36 *
37 * Notes:
38 *
39 * 1) This example requires libcurl 7.34.0 or above.
40 * 2) Not all email servers support this command and even if your email server
41 *    does support it, it may respond with a 252 response code even though the
42 *    address does not exist.
43 */
44
45int main(void)
46{
47  CURL *curl;
48  CURLcode res;
49  struct curl_slist *recipients = NULL;
50
51  curl = curl_easy_init();
52  if(curl) {
53    /* This is the URL for your mailserver */
54    curl_easy_setopt(curl, CURLOPT_URL, "smtp://mail.example.com");
55
56    /* Note that the CURLOPT_MAIL_RCPT takes a list, not a char array  */
57    recipients = curl_slist_append(recipients, "<recipient@example.com>");
58    curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, recipients);
59
60    /* Perform the VRFY */
61    res = curl_easy_perform(curl);
62
63    /* Check for errors */
64    if(res != CURLE_OK)
65      fprintf(stderr, "curl_easy_perform() failed: %s\n",
66              curl_easy_strerror(res));
67
68    /* Free the list of recipients */
69    curl_slist_free_all(recipients);
70
71    /* curl will not send the QUIT command until you call cleanup, so you
72     * should be able to reuse this connection for additional requests. It may
73     * not be a good idea to keep the connection open for a long time though
74     * (more than a few minutes may result in the server timing out the
75     * connection) and you do want to clean up in the end.
76     */
77    curl_easy_cleanup(curl);
78  }
79
80  return 0;
81}
82