CURLOPT_PRIVATE.3: provide an example

docs/libcurl/opts/CURLOPT_PRIVATE.3

@@ -5,7 +5,7 @@
 .\" *                            | (__| |_| |  _ <| |___
 .\" *                             \___|\___/|_| \_\_____|
 .\" *
-.\" * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
+.\" * Copyright (C) 1998 - 2015, 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
@@ -37,7 +37,22 @@ NULL
 .SH PROTOCOLS
 All
 .SH EXAMPLE
-TODO
+.nf
+CURL *curl = curl_easy_init();
+struct private secrets;
+if(curl) {
+  struct private *extracted;
+  curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");
+
+  /* store a pointer to our private struct */
+  curl_easy_setopt(curl, CURLOPT_PRIVATE, &secrets);
+
+  curl_easy_perform(curl);
+
+  /* we can extract the private pointer again too */
+  curl_easy_getinfo(curl, CURLINFO_PRIVATE, &extracted);
+}
+.fi
 .SH AVAILABILITY
 Added in 7.10.3
 .SH RETURN VALUE