1 files changed, 34 insertions, 0 deletions
diff --git a/boost/histogram/detail/cat.hpp b/boost/histogram/detail/cat.hpp
new file mode 100644
index 0000000000..f977c01406
--- /dev/null
+++ b/boost/histogram/detail/cat.hpp
@@ -0,0 +1,34 @@
+// Copyright 2015-2017 Hans Dembinski
+//
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt
+// or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_HISTOGRAM_DETAIL_CAT_HPP
+#define BOOST_HISTOGRAM_DETAIL_CAT_HPP
+
+#include <boost/config.hpp>
+#include <sstream>
+
+namespace boost {
+namespace histogram {
+namespace detail {
+BOOST_ATTRIBUTE_UNUSED inline void cat_impl(std::ostringstream&) {}
+
+template <typename T, typename... Ts>
+void cat_impl(std::ostringstream& os, const T& t, const Ts&... ts) {
+  os << t;
+  cat_impl(os, ts...);
+}
+
+template <typename... Ts>
+std::string cat(const Ts&... args) {
+  std::ostringstream os;
+  cat_impl(os, args...);
+  return os.str();
+}
+} // namespace detail
+} // namespace histogram
+} // namespace boost
+
+#endif