--- libgig/trunk/src/RIFF.h	2021/06/07 18:57:17	3915
+++ libgig/trunk/src/RIFF.h	2021/06/07 19:42:17	3916
@@ -406,6 +406,7 @@
                 stream_mode_t Mode; ///< State of handles (ro, rw, closed).
             };
             struct IO : HandlePair {
+                bool isPerThread; ///< Whether SetIOPerThread(true) was called.
                 mutable std::map<std::thread::id,HandlePair> byThread; ///< Optional: Individual file handle pair for each thread separately.
                 mutable std::mutex mutex; ///< For protecting concurrent changes on the @c byThread map itself and replacing handles.
             } io;
@@ -434,6 +435,7 @@
             int FileOffsetSizeFor(file_offset_t fileSize) const;
             void Cleanup();
             HandlePair& FileHandlePairUnsafeRef();
+            bool SetModeInternal(stream_mode_t NewMode, bool* pResetPos);
     };
 
     /**