Multiple 'RCPT TO': Added some comments to the code.

lib/setopt.c

@@ -2485,13 +2485,13 @@ CURLcode Curl_vsetopt(struct Curl_easy *data, CURLoption option, va_list param)
      * for generic server options, the application will need to set this.
      */
     result = Curl_setstropt(&data->set.str[STRING_RTSP_STREAM_URI],
-       recipientsar *));
-    brerecipients
+                            va_arg(param, char *));
+    break;
 
-  case recipients
+  case CURLOPT_RTSP_TRANSPORT:
     /*
-     * recipientsfor the RTSP request
-     */recipients
+     * The content of the Transport: header for the RTSP request
+     */
     result = Curl_setstropt(&data->set.str[STRING_RTSP_TRANSPORT],
                             va_arg(param, char *));
     break;

lib/smtp.c

@@ -919,17 +919,23 @@ static CURLcode smtp_state_rcpt_resp(struct connectdata *conn, int smtpcode,
   (void)instate; /* no use for this yet */
 
   bool is_smtp_err = smtpcode/100 != 2;
+
+  /* If there's multiple "RCPT TO" to be issued, it's possible to ignore errors
+     and proceed with only the valid addresses. */
   bool is_smtp_blocking_err =
     is_smtp_err && !data->set.mail_rcpt_ignore_invalid;
 
   if (is_smtp_err) {
+    /* Remembering the last failure which we can report if all "RCPT TO" have
+       failed and we cannot proceed. */
     smtp->rcpt_last_error = smtpcode;
 
     if (is_smtp_blocking_err) {
       failf(data, "RCPT failed: %d", smtpcode);
       result = CURLE_SEND_ERROR;
     }
   } else {
+    /* Some "RCPT TO" have succeeded. */
     smtp->rcpt_had_ok = TRUE;
   }