Improve archive destruction

include/cereal/archives/json.hpp

@@ -169,15 +169,36 @@ namespace cereal
         itsNodeStack.push(NodeType::StartObject);
       }
 
-      //! Destructor, flushes the JSON
-      ~JSONOutputArchive() CEREAL_NOEXCEPT
+      //! Explicitly finishes the JSON output and flushes to the stream
+      /*! This method can be used to detect and handle errors that occur during
+          finalization of the JSON output, similar to std::fstream::close().
+          If not called explicitly, the destructor will attempt the same
+          finalization but will silently swallow any exceptions.
+
+          It is safe to call close() multiple times; subsequent calls are no-ops.
+
+          @throws RapidJSONException if rapidjson encounters an error during finalization */
+      void close()
       {
+        if( itsClosed )
+          return;
+        itsClosed = true;
+
         if (itsNodeStack.top() == NodeType::InObject)
           itsWriter.EndObject();
         else if (itsNodeStack.top() == NodeType::InArray)
           itsWriter.EndArray();
       }
 
+      //! Destructor, flushes the JSON
+      /*! Silently catches any exceptions to guarantee noexcept.
+          Call close() explicitly before destruction to detect errors. */
+      ~JSONOutputArchive() CEREAL_NOEXCEPT
+      {
+        try { close(); }
+        catch(...) {}
+      }
+
       //! Saves some binary data, encoded as a base64 string, with an optional name
       /*! This will create a new node, optionally named, and insert a value that consists of
           the data encoded as a base64 string */
@@ -385,6 +406,7 @@ namespace cereal
       char const * itsNextName;            //!< The next name
       std::stack<uint32_t> itsNameCounter; //!< Counter for creating unique names for unnamed nodes
       std::stack<NodeType> itsNodeStack;
+      bool itsClosed = false;              //!< Whether close() has been called
   }; // JSONOutputArchive
 
   // ######################################################################

include/cereal/archives/xml.hpp

@@ -185,14 +185,36 @@ namespace cereal
         itsOS.precision( options.itsPrecision );
       }
 
-      //! Destructor, flushes the XML
-      ~XMLOutputArchive() CEREAL_NOEXCEPT
+      //! Explicitly finishes the XML output and flushes to the stream
+      /*! This method can be used to detect and handle errors that occur during
+          finalization of the XML output (e.g., stream I/O failures), similar
+          to std::fstream::close().
+          If not called explicitly, the destructor will attempt the same
+          finalization but will silently swallow any exceptions.
+
+          It is safe to call close() multiple times; subsequent calls are no-ops.
+
+          @throws std::exception if the stream operations fail */
+      void close()
       {
+        if( itsClosed )
+          return;
+        itsClosed = true;
+
         const int flags = itsIndent ? 0x0 : rapidxml::print_no_indenting;
         rapidxml::print( itsStream, itsXML, flags );
         itsXML.clear();
       }
 
+      //! Destructor, flushes the XML
+      /*! Silently catches any exceptions to guarantee noexcept.
+          Call close() explicitly before destruction to detect errors. */
+      ~XMLOutputArchive() CEREAL_NOEXCEPT
+      {
+        try { close(); }
+        catch(...) {}
+      }
+
       //! Saves some binary data, encoded as a base64 string, with an optional name
       /*! This can be called directly by users and it will automatically create a child node for
           the current XML node, populate it with a base64 encoded string, and optionally name
@@ -361,6 +383,7 @@ namespace cereal
       bool itsOutputType;              //!< Controls whether type information is printed
       bool itsIndent;                  //!< Controls whether indenting is used
       bool itsSizeAttributes;          //!< Controls whether lists have a size attribute
+      bool itsClosed = false;          //!< Whether close() has been called
   }; // XMLOutputArchive
 
   // ######################################################################