CURLINFO_TLS_SSL_PTR.3: improve the example

The previous example was a little bit confusing, because SSL* structure
(or other "in use" SSL connection pointer) is not accessible after the
transfer is completed, therefore working with the raw TLS library
specific pointer needs to be done during transfer.

Closes #2690

1 files changed, 27 insertions, 8 deletions

diff --git a/docs/libcurl/opts/CURLINFO_TLS_SSL_PTR.3 b/docs/libcurl/opts/CURLINFO_TLS_SSL_PTR.3
index 59ddd599c..c601e4fcf 100644
--- a/docs/libcurl/opts/CURLINFO_TLS_SSL_PTR.3
+++ b/docs/libcurl/opts/CURLINFO_TLS_SSL_PTR.3
@@ -5,7 +5,7 @@
 .\" *                            | (__| |_| |  _ <| |___
 .\" *                             \___|\___/|_| \_\_____|
 .\" *
-.\" * Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
+.\" * Copyright (C) 1998 - 2018, 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
@@ -129,14 +129,33 @@ https://github.com/curl/curl/issues/685
 All TLS-based
 .SH EXAMPLE
 .nf
-CURL *curl = curl_easy_init();
-if(curl) {
+#include <curl/curl.h>
+#include <openssl/ssl.h>
+
+CURL *curl;
+static size_t wf(void *ptr, size_t size, size_t nmemb, void *stream)
+{
+  const struct curl_tlssessioninfo *info = NULL;
+  CURLcode res = curl_easy_getinfo(curl, CURLINFO_TLS_SSL_PTR, &info);
+  if(info && !res) {
+    if(CURLSSLBACKEND_OPENSSL == info->backend) {
+       printf("OpenSSL ver. %s\\n", SSL_get_version((SSL*)info->internals));
+    }
+  }
+  return size * nmemb;
+}
+
+int main(int argc, char** argv)
+{
   CURLcode res;
-  struct curl_tlssessioninfo *tls;
-  curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
-  res = curl_easy_perform(curl);
-  curl_easy_getinfo(curl, CURLINFO_TLS_SSL_PTR, &tls);
-  curl_easy_cleanup(curl);
+  curl = curl_easy_init();
+  if(curl) {
+    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
+    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, wf);
+    res = curl_easy_perform(curl);
+    curl_easy_cleanup(curl);
+  }
+  return res;
 }
 .fi
 .SH AVAILABILITY