prefer std::string for setComment()

in case of embedded nulls
diff --git a/include/json/value.h b/include/json/value.h
index d91ccc4..26bb38b 100644
--- a/include/json/value.h
+++ b/include/json/value.h
@@ -512,6 +512,7 @@
   //# endif
 
   /// \deprecated Always pass len.
+  JSONCPP_DEPRECATED("Use setComment(std::string const&) instead.")
   void setComment(const char* comment, CommentPlacement placement);
   /// Comments must be //... or /* ... */
   void setComment(const char* comment, size_t len, CommentPlacement placement);
diff --git a/src/test_lib_json/main.cpp b/src/test_lib_json/main.cpp
index 71e9491..f0e3436 100644
--- a/src/test_lib_json/main.cpp
+++ b/src/test_lib_json/main.cpp
@@ -1542,7 +1542,7 @@
 
 JSONTEST_FIXTURE(ValueTest, CommentBefore) {
   Json::Value val; // fill val
-  val.setComment("// this comment should appear before", Json::commentBefore);
+  val.setComment(std::string("// this comment should appear before"), Json::commentBefore);
   Json::StreamWriterBuilder wbuilder;
   wbuilder.settings_["commentStyle"] = "All";
   {