Update message_t range constructor to accept char containers but ignore (#673)

Author: cacharle

tests/message.cpp

@@ -48,6 +48,23 @@ TEST_CASE("message constructor with iterators", "[message]")
     CHECK(0 == memcmp(data, hi_msg.data(), 2));
 }
 
+TEST_CASE("message constructor with ranges", "[message]")
+{
+    SECTION("trivial type")
+    {
+        const std::vector<int> v{1, 2, 3};
+        const zmq::message_t msg(v);
+        CHECK(3u * sizeof(int) == msg.size());
+    }
+    SECTION("char type")
+    {
+        const std::vector<char> hi{'H', 'i'};
+        const zmq::message_t hi_msg(hi);
+        CHECK(2u == hi_msg.size());
+        CHECK(0 == memcmp(data, hi_msg.data(), 2));
+    }
+}
+
 TEST_CASE("message constructor with size", "[message]")
 {
     const zmq::message_t msg(5);

zmq.hpp

@@ -492,8 +492,11 @@ class message_t
              typename = typename std::enable_if<
                detail::is_range<Range>::value
                && ZMQ_IS_TRIVIALLY_COPYABLE(detail::range_value_t<Range>)
-               && !detail::is_char_type<detail::range_value_t<Range>>::value
-               && !std::is_same<Range, message_t>::value>::type>
+               && !std::is_same<Range, message_t>::value
+#if CPPZMQ_HAS_STRING_VIEW
+               && !std::is_same<Range, std::string_view>::value
+#endif
+               && !std::is_same<Range, std::string>::value>::type>
     explicit message_t(const Range &rng) :
         message_t(detail::ranges::begin(rng), detail::ranges::end(rng))
     {