examples: Added SMTP EXPN command example

docs/examples/Makefile.inc

@@ -4,8 +4,9 @@ check_PROGRAMS = 10-at-a-time anyauthput cookie_interface debug fileupload \
   https multi-app multi-debugcallback multi-double multi-post multi-single \
   persistant post-callback postit2 sepheaders simple simplepost simplessl  \
   sendrecv httpcustomheader certinfo chkspeed ftpgetinfo ftp-wildcard \
-  smtp-multi simplesmtp smtp-tls rtsp externalsocket resolve \
-  progressfunc pop3s pop3slist imap url2file sftpget ftpsget postinmemory
+  smtp-multi simplesmtp smtp-tls smtp-vrfy smtp-expn rtsp externalsocket \
+  resolve progressfunc pop3s pop3slist imap 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.

docs/examples/smtp-expn.c

@@ -0,0 +1,74 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2013, 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 <string.h>
+#include <curl/curl.h>
+
+/* This is a simple example showing how to expand an email mailing list.
+ *
+ * Notes:
+ *
+ * 1) This example requires libcurl v7.34.0 or above.
+ * 2) Not all email servers support this command.
+ */
+
+int main(void)
+{
+  CURL *curl;
+  CURLcode res;
+  struct curl_slist *recipients = NULL;
+
+  curl = curl_easy_init();
+  if(curl) {
+    /* This is the URL for your mailserver - you can also use an smtps:// URL
+     * here */
+    curl_easy_setopt(curl, CURLOPT_URL, "smtp://mail.example.net");
+
+    /* Note that the CURLOPT_MAIL_RCPT takes a list, not a char array  */
+    recipients = curl_slist_append(recipients, "Friends");
+    curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, recipients);
+
+    /* Set the EXPN command */
+    curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "EXPN");
+
+    /* 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));
+
+    /* Free the list of recipients */
+    curl_slist_free_all(recipients);
+
+    /* Curl won't send the QUIT command until you call cleanup, so you should
+     * be able to re-use this connection for additional requests. It may not be
+     * a good idea to keep the connection open for a very long time though
+     * (more than a few minutes may result in the server timing out the
+     * connection) and you do want to clean up in the end.
+     */
+    curl_easy_cleanup(curl);
+  }
+
+  return 0;
+}

docs/examples/smtp-vrfy.c

@@ -28,7 +28,7 @@
  *
  * Notes:
  *
- * 1) That this example requires libcurl v7.34.0 or above.
+ * 1) This example requires libcurl v7.34.0 or above.
  * 2) Not all email servers support this command and even if your email server
  *    does support it, it may respond with a 252 response code even though the
  *    address doesn't exist.