examples: Added POP3 NOOP example

  sendrecv httpcustomheader certinfo chkspeed ftpgetinfo ftp-wildcard \

  smtp-multi smtp-send smtp-ssl smtp-tls smtp-vrfy smtp-expn rtsp \

  externalsocket resolve progressfunc pop3-retr pop3-list pop3-uidl pop3-dele \

  pop3-top pop3-stat pop3-ssl imap-list imap-fetch imap-store imap-append \

  imap-examine imap-search imap-create imap-delete imap-copy imap-ssl imap-tls \

  url2file sftpget ftpsget postinmemory

  pop3-top pop3-stat pop3-noop pop3-ssl imap-list imap-fetch imap-store \

  imap-append imap-examine imap-search imap-create imap-delete imap-copy \

  imap-ssl imap-tls url2file sftpget ftpsget postinmemory

# These examples require external dependencies that may not be commonly

# available on POSIX systems, so don't bother attempting to compile them here.

/***************************************************************************

 *                                  _   _ ____  _

 *  Project                     ___| | | |  _ \| |

 *                             / __| | | | |_) | |

 *                            | (__| |_| |  _ <| |___

 *                             \___|\___/|_| \_\_____|

 *

 * Copyright (C) 1998 - 2014, 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 http://curl.haxx.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.

 *

 ***************************************************************************/

#include <stdio.h>

#include <curl/curl.h>

/* This is a simple example showing how to perform a noop using libcurl's POP3

 * capabilities.

 *

 * Note that this example requires libcurl 7.26.0 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 is just the server URL */

    curl_easy_setopt(curl, CURLOPT_URL, "pop3://pop.example.com");

    /* Set the NOOP command */

    curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "NOOP");

    /* Do not perform a transfer as NOOP returns no data */

    curl_easy_setopt(curl, CURLOPT_NOBODY, 1L);

    /* Perform the custom request */

    res = curl_easy_perform(curl);

    /* Check for errors */

    if(res != CURLE_OK)

      fprintf(stderr, "curl_easy_perform() failed: %s\n",

              curl_easy_strerror(res));

    /* Always cleanup */

    curl_easy_cleanup(curl);

  }

  return (int)res;

}