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curl / libcurl / API / Examples / pop3-ssl.c


 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 * Copyright (C) Daniel Stenberg, <>, 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
 * 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
/* <DESC>
 * Get POP3 email using implicit SSL
 * </DESC>
#include <stdio.h>
#include <curl/curl.h>
/* This is a simple example showing how to retrieve mail using libcurl's POP3
 * capabilities. It builds on the pop3-retr.c example adding transport
 * security to protect the authentication details from being snooped.
 * Note that this example requires libcurl 7.20.0 or above.
int main(void)
  CURL *curl;
  CURLcode res = CURLE_OK;
  curl = curl_easy_init();
  if(curl) {
    /* Set username and password */
    curl_easy_setopt(curl, CURLOPT_USERNAME, "user");
    curl_easy_setopt(curl, CURLOPT_PASSWORD, "secret");
    /* This retrieves message 1 from the user's mailbox. Note the use of
     * pop3s:// rather than pop3:// to request a SSL based connection. */
    curl_easy_setopt(curl, CURLOPT_URL, "pop3s://");
    /* If you want to connect to a site who is not using a certificate that is
     * signed by one of the certs in the CA bundle you have, you can skip the
     * verification of the server's certificate. This makes the connection
     * If you have a CA cert for the server stored someplace else than in the
     * default bundle, then the CURLOPT_CAPATH option might come handy for
     * you. */
    curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
    /* If the site you are connecting to uses a different host name that what
     * they have mentioned in their server certificate's commonName (or
     * subjectAltName) fields, libcurl refuses to connect. You can skip this
     * check, but it makes the connection insecure. */
    curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
    /* Since the traffic is encrypted, it is useful to turn on debug
     * information within libcurl to see what is happening during the
     * transfer */
    curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
    /* Perform the retr */
    res = curl_easy_perform(curl);
    /* Check for errors */
    if(res != CURLE_OK)
      fprintf(stderr, "curl_easy_perform() failed: %s\n",
    /* Always cleanup */
  return (int)res;


This source code example is simplified and ignores return codes and error checks to a large extent. We do this to highlight the libcurl function calls and related options and reduce unrelated code.

A real-world application will of course properly check every return value and exit correctly at the first serious error.