examples: add http3.c, altsvc.c and http3-present.c

Closes #4221

1 files changed, 47 insertions, 0 deletions

diff --git a/docs/examples/http3-present.c b/docs/examples/http3-present.c
new file mode 100644
index 000000000..857952dc7
--- /dev/null
+++ b/docs/examples/http3-present.c
@@ -0,0 +1,47 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2019, 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 https://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.
+ *
+ ***************************************************************************/
+/* <DESC>
+ * Checks if HTTP/3 support is present in libcurl.
+ * </DESC>
+ */
+#include <stdio.h>
+#include <curl/curl.h>
+
+int main(void)
+{
+  curl_version_info_data *ver;
+
+  curl_global_init(CURL_GLOBAL_ALL);
+
+  ver = curl_version_info(CURLVERSION_NOW);
+  if(ver->features & CURL_VERSION_HTTP2)
+    printf("HTTP/2 support is present\n");
+
+  if(ver->features & CURL_VERSION_HTTP3)
+    printf("HTTP/3 support is present\n");
+
+  if(ver->features & CURL_VERSION_ALTSVC)
+    printf("Alt-svc support is present\n");
+
+  curl_global_cleanup();
+  return 0;
+}