Fix warning C4239: nonstandard extension used: 'argument': conversion…

… from 'slog::detail::`anonymous-namespace'::log<`anonymous-namespace'::dull_gate,-2147483647>' to 'slog::log_statement &'

message : A non-const reference may only be bound to an lvalue

Development/cmake/NmosCppTest.cmake

@@ -52,6 +52,7 @@ set(NMOS_CPP_TEST_NMOS_TEST_SOURCES
     nmos/test/query_api_test.cpp
     nmos/test/sdp_test_utils.cpp
     nmos/test/sdp_utils_test.cpp
+    nmos/test/slog_test.cpp
     nmos/test/system_resources_test.cpp
     nmos/test/video_jxsv_test.cpp
     )

Development/nmos/slog.h

@@ -16,6 +16,10 @@ namespace slog
     {
         return s << utility::conversions::to_utf8string(u16s);
     }
+    inline log_statement& operator<<(log_statement&& s, const utf16string& u16s)
+    {
+        return s << u16s;
+    }
 }
 
 namespace nmos
@@ -25,6 +29,10 @@ namespace nmos
     {
         return s << id_type.second.name << ": " << id_type.first;
     }
+    inline slog::log_statement& operator<<(slog::log_statement&& s, const std::pair<nmos::id, nmos::type>& id_type)
+    {
+        return s << id_type;
+    }
 
     // Log message categories
     typedef std::string category;

Development/nmos/test/slog_test.cpp

@@ -0,0 +1,26 @@
+// The first "test" is of course whether the header compiles standalone
+#include "nmos/slog.h"
+
+#include "bst/test/test.h"
+
+namespace
+{
+    struct dull_gate
+    {
+        bool pertinent(slog::severity level) const { return true; }
+        void log(const slog::log_message& message) {}
+    };
+}
+
+BST_TEST_CASE(testSlogLog)
+{
+    dull_gate gate;
+    const auto str = utility::string_t{ U("foo") };
+    const auto it = std::make_pair(nmos::id{ U("bar") }, nmos::types::node);
+    // log statement
+    slog::log<SLOG_LOGGING_SEVERITY>(gate, SLOG_FLF) << str << 42 << str;
+    slog::log<SLOG_LOGGING_SEVERITY>(gate, SLOG_FLF) << it << 42 << it;
+    // no log statement
+    slog::log<SLOG_LOGGING_SEVERITY - 1>(gate, SLOG_FLF) << str << 42 << str;
+    slog::log<SLOG_LOGGING_SEVERITY - 1>(gate, SLOG_FLF) << it << 42 << it;
+}