build: switch to C++17
Change-Id: Id6217b5c993f3e4726e89773128b565e5f136bb6
diff --git a/core/common.hpp b/core/common.hpp
index 34da654..614dd4e 100644
--- a/core/common.hpp
+++ b/core/common.hpp
@@ -1,6 +1,6 @@
/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
- * Copyright (c) 2014-2021, Regents of the University of California,
+ * Copyright (c) 2014-2022, Regents of the University of California,
* Arizona Board of Regents,
* Colorado State University,
* University Pierre & Marie Curie, Sorbonne University,
@@ -46,6 +46,7 @@
#include <memory>
#include <stdexcept>
#include <string>
+#include <string_view>
#include <utility>
#include <vector>
diff --git a/core/version.cpp.in b/core/version.cpp.in
index 8abef00..04fd901 100644
--- a/core/version.cpp.in
+++ b/core/version.cpp.in
@@ -19,10 +19,8 @@
#include "core/version.hpp"
-namespace ndn {
-namespace tools {
+namespace ndn::tools {
const char VERSION[] = "@VERSION_BUILD@";
-} // namespace tools
-} // namespace ndn
+} // namespace ndn::tools
diff --git a/core/version.hpp b/core/version.hpp
index 03058f6..2a20a1a 100644
--- a/core/version.hpp
+++ b/core/version.hpp
@@ -22,15 +22,13 @@
#include "core/common.hpp"
-namespace ndn {
-namespace tools {
+namespace ndn::tools {
/**
* \brief The version of ndn-tools.
*/
extern const char VERSION[];
-} // namespace tools
-} // namespace ndn
+} // namespace ndn::tools
#endif // NDN_TOOLS_CORE_VERSION_HPP