diff --git a/src/DDF/DDF_IOStream.cxx b/src/DDF/DDF_IOStream.cxx
index 61d010421f..d116d3db96 100644
--- a/src/DDF/DDF_IOStream.cxx
+++ b/src/DDF/DDF_IOStream.cxx
@@ -281,7 +281,7 @@ void DDF_IOStream::ReadExtendedLine(TCollection_ExtendedString& buffer)
 
 void DDF_IOStream::ReadChar(TCollection_AsciiString& buffer, const Standard_Integer rsize)
 {
-  char             c;
+  char c = '\0';
   Standard_Integer ccount = 0;
 
   buffer.Clear();
@@ -1216,7 +1216,7 @@ Storage_Error DDF_IOStream::BeginReadDataSection()
 void DDF_IOStream::ReadPersistentObjectHeader(Standard_Integer& aRef,
 					  Standard_Integer& aType) 
 {
-  char c;
+  char c = '\0';
 
   myIStream->get(c);
 
@@ -1256,7 +1256,7 @@ void DDF_IOStream::ReadPersistentObjectHeader(Standard_Integer& aRef,
 
 void DDF_IOStream::BeginReadPersistentObjectData() 
 {
-  char c;
+  char c = '\0';
   myIStream->get(c);
   while (c != '(') {
     if (IsEnd() || (c != ' ') || (c == '\n')) {
@@ -1273,7 +1273,7 @@ void DDF_IOStream::BeginReadPersistentObjectData()
 
 void DDF_IOStream::BeginReadObjectData() 
 {
-  char c;
+  char c = '\0';
   myIStream->get(c);
   while (c != '(') {
     if (IsEnd() || (c != ' ') || (c == '\n')) {
@@ -1290,7 +1290,7 @@ void DDF_IOStream::BeginReadObjectData()
 
 void DDF_IOStream::EndReadObjectData() 
 {
-  char c;
+  char c = '\0';
   myIStream->get(c);
   while (c != ')') {
     if (IsEnd() || (c != ' ') || (c == '\n')) {
@@ -1307,7 +1307,7 @@ void DDF_IOStream::EndReadObjectData()
 
 void DDF_IOStream::EndReadPersistentObjectData() 
 {
-  char c;
+  char c = '\0';
 
   myIStream->get(c);
   while (c != ')') {
diff --git a/src/FSD/FSD_CmpFile.cxx b/src/FSD/FSD_CmpFile.cxx
index 594fe0a7b4..e23394c34b 100644
--- a/src/FSD/FSD_CmpFile.cxx
+++ b/src/FSD/FSD_CmpFile.cxx
@@ -325,7 +325,7 @@ void FSD_CmpFile::EndWritePersistentObjectData()
 void FSD_CmpFile::ReadPersistentObjectHeader(Standard_Integer& aRef,
                                              Standard_Integer& aType)
 {
-  char c;
+  char c = '\0';
 
   myStream.get(c);
 
@@ -388,7 +388,7 @@ void FSD_CmpFile::EndReadObjectData()
 
 void FSD_CmpFile::EndReadPersistentObjectData()
 {
-  char c;
+  char c = '\0';
 
   myStream.get(c);
   while (c != '\n' && (c != '\r')) {
diff --git a/src/FSD/FSD_File.cxx b/src/FSD/FSD_File.cxx
index 10afce93a3..c02ee5c24f 100644
--- a/src/FSD/FSD_File.cxx
+++ b/src/FSD/FSD_File.cxx
@@ -280,7 +280,7 @@ void FSD_File::ReadExtendedLine(TCollection_ExtendedString& buffer)
 
 void FSD_File::ReadChar(TCollection_AsciiString& buffer, const Standard_Size rsize)
 {
-  char             c;
+  char c = '\0';
   Standard_Size ccount = 0;
 
   buffer.Clear();
@@ -1234,7 +1234,7 @@ Storage_Error FSD_File::BeginReadDataSection()
 void FSD_File::ReadPersistentObjectHeader(Standard_Integer& aRef,
 					  Standard_Integer& aType) 
 {
-  char c;
+  char c = '\0';
 
   myStream.get(c);
 
@@ -1277,7 +1277,7 @@ void FSD_File::ReadPersistentObjectHeader(Standard_Integer& aRef,
 
 void FSD_File::BeginReadPersistentObjectData() 
 {
-  char c;
+  char c = '\0';
   myStream.get(c);
   while (c != '(') {
     if (IsEnd() || (c != ' ') || (c == '\n')) {
@@ -1296,8 +1296,7 @@ void FSD_File::BeginReadPersistentObjectData()
 
 void FSD_File::BeginReadObjectData() 
 {
-
-  char c;
+  char c = '\0';
   myStream.get(c);
   while (c != '(') {
     if (IsEnd() || (c != ' ') || (c == '\n')) {
@@ -1316,8 +1315,7 @@ void FSD_File::BeginReadObjectData()
 
 void FSD_File::EndReadObjectData() 
 {
-
-  char c;
+  char c = '\0';
   myStream.get(c);
   while (c != ')') {
     if (IsEnd() || (c != ' ') || (c == '\n')) {
@@ -1336,8 +1334,7 @@ void FSD_File::EndReadObjectData()
 
 void FSD_File::EndReadPersistentObjectData() 
 {
-
-  char c;
+  char c = '\0';
 
   myStream.get(c);
   while (c != ')') {
diff --git a/src/ShapePersistent/ShapePersistent_HArray1.hxx b/src/ShapePersistent/ShapePersistent_HArray1.hxx
index 6ddbf7ccb0..a1a4b794f1 100644
--- a/src/ShapePersistent/ShapePersistent_HArray1.hxx
+++ b/src/ShapePersistent/ShapePersistent_HArray1.hxx
@@ -49,8 +49,10 @@ public:
 };
 
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, Poly_Triangle& theTriangle)
+  (StdObjMgt_ReadData& theReadData, Poly_Triangle& theTriangle)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
+
   Standard_Integer N1, N2, N3;
   theReadData >> N1 >> N2 >> N3;
   theTriangle.Set (N1, N2, N3);
@@ -58,8 +60,10 @@ inline StdObjMgt_ReadData& operator >>
 }
 
 inline StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const Poly_Triangle& theTriangle)
+  (StdObjMgt_WriteData& theWriteData, const Poly_Triangle& theTriangle)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   Standard_Integer N1, N2, N3;
   theTriangle.Get(N1, N2, N3);
   theWriteData << N1 << N2 << N3;
diff --git a/src/StdLPersistent/StdLPersistent_HArray1.cxx b/src/StdLPersistent/StdLPersistent_HArray1.cxx
index 7318651fa5..c26202183c 100644
--- a/src/StdLPersistent/StdLPersistent_HArray1.cxx
+++ b/src/StdLPersistent/StdLPersistent_HArray1.cxx
@@ -24,13 +24,13 @@ void StdLPersistent_HArray1::base::Read (StdObjMgt_ReadData& theReadData)
   theReadData >> aLowerBound >> anUpperBound;
   createArray (aLowerBound, anUpperBound);
 
-  StdObjMgt_ReadData::Object anObjectData (theReadData);
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
 
   Standard_Integer aSize;
-  anObjectData >> aSize;
+  theReadData >> aSize;
 
   for (Standard_Integer i = aLowerBound; i <= anUpperBound; i++)
-    readValue (anObjectData, i);
+    readValue (theReadData, i);
 }
 
 //=======================================================================
@@ -42,10 +42,10 @@ void StdLPersistent_HArray1::base::Write (StdObjMgt_WriteData& theWriteData) con
   Standard_Integer aLowerBound = lowerBound(), anUpperBound = upperBound();
   theWriteData << aLowerBound << anUpperBound;
 
-  StdObjMgt_WriteData::Object anObjectData(theWriteData);
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
 
   Standard_Integer aSize = anUpperBound - aLowerBound + 1;
-  anObjectData << aSize;
+  theWriteData << aSize;
 
   for (Standard_Integer i = aLowerBound; i <= anUpperBound; i++)
     writeValue(theWriteData, i);
diff --git a/src/StdLPersistent/StdLPersistent_HArray2.cxx b/src/StdLPersistent/StdLPersistent_HArray2.cxx
index cde9009dd8..dffa7662d5 100644
--- a/src/StdLPersistent/StdLPersistent_HArray2.cxx
+++ b/src/StdLPersistent/StdLPersistent_HArray2.cxx
@@ -27,14 +27,14 @@ void StdLPersistent_HArray2::base::Read (StdObjMgt_ReadData& theReadData)
   theReadData >> aLowerRow >> aLowerCol >> anUpperRow >> anUpperCol;
   createArray (aLowerRow, aLowerCol, anUpperRow, anUpperCol);
 
-  StdObjMgt_ReadData::Object anObjectData (theReadData);
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
 
   Standard_Integer aSize;
-  anObjectData >> aSize;
+  theReadData >> aSize;
 
   for (Standard_Integer aRow = aLowerRow; aRow <= anUpperRow; aRow++)
     for (Standard_Integer aCol = aLowerCol; aCol <= anUpperCol; aCol++)
-      readValue (anObjectData, aRow, aCol);
+      readValue (theReadData, aRow, aCol);
 }
 
 //=======================================================================
@@ -48,12 +48,12 @@ void StdLPersistent_HArray2::base::Write (StdObjMgt_WriteData& theWriteData) con
   upperBound(anUpperRow, anUpperCol);
   theWriteData << aLowerRow << aLowerCol << anUpperRow << anUpperCol;
 
-  StdObjMgt_WriteData::Object anObjectData(theWriteData);
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
 
   Standard_Integer aSize = (anUpperRow - aLowerRow + 1) * (anUpperCol - aLowerCol + 1);
-  anObjectData << aSize;
+  theWriteData << aSize;
 
   for (Standard_Integer aRow = aLowerRow; aRow <= anUpperRow; aRow++)
     for (Standard_Integer aCol = aLowerCol; aCol <= anUpperCol; aCol++)
-      writeValue(anObjectData, aRow, aCol);
+      writeValue(theWriteData, aRow, aCol);
 }
diff --git a/src/StdLPersistent/StdLPersistent_HString.cxx b/src/StdLPersistent/StdLPersistent_HString.cxx
index 436f1ca2fc..a14367796c 100644
--- a/src/StdLPersistent/StdLPersistent_HString.cxx
+++ b/src/StdLPersistent/StdLPersistent_HString.cxx
@@ -26,16 +26,16 @@ template <class StringClass, typename CharType>
 void StdLPersistent_HString::instance<StringClass, CharType>::Read
   (StdObjMgt_ReadData& theReadData)
 {
-  StdObjMgt_ReadData::Object anObjectData (theReadData);
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
 
   Standard_Integer aSize;
-  anObjectData >> aSize;
+  theReadData >> aSize;
   myValue = new StringClass (aSize, 0);
 
   for (Standard_Integer i = 1; i <= aSize; i++)
   {
     CharType aChar;
-    anObjectData >> aChar;
+    theReadData >> aChar;
     myValue->SetValue (i, aChar);
   }
 }
@@ -48,15 +48,15 @@ template <class StringClass, typename CharType>
 void StdLPersistent_HString::instance<StringClass, CharType>::Write
   (StdObjMgt_WriteData& theWriteData) const
 {
-  StdObjMgt_WriteData::Object anObjectData(theWriteData);
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
 
   Standard_Integer aSize = myValue->Length();
-  anObjectData << aSize;
+  theWriteData << aSize;
 
   for (Standard_Integer i = 1; i <= aSize; i++)
   {
     CharType aChar (0);
-    anObjectData << aChar;
+    theWriteData << aChar;
   }
 }
 
diff --git a/src/StdObjMgt/StdObjMgt_ReadData.cxx b/src/StdObjMgt/StdObjMgt_ReadData.cxx
index 9bb92145b1..5d80270ce1 100644
--- a/src/StdObjMgt/StdObjMgt_ReadData.cxx
+++ b/src/StdObjMgt/StdObjMgt_ReadData.cxx
@@ -47,8 +47,10 @@ Handle(StdObjMgt_Persistent) StdObjMgt_ReadData::ReadReference()
 //purpose  : Read persistent data from a file
 //=======================================================================
 StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, Standard_GUID& theGUID)
+  (StdObjMgt_ReadData& theReadData, Standard_GUID& theGUID)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
+
   Standard_Integer      a32b;
   Standard_ExtCharacter a16b[3];
   Standard_Character    a8b [6];
diff --git a/src/StdObjMgt/StdObjMgt_ReadData.hxx b/src/StdObjMgt/StdObjMgt_ReadData.hxx
index 8582e14df7..f81d379a02 100644
--- a/src/StdObjMgt/StdObjMgt_ReadData.hxx
+++ b/src/StdObjMgt/StdObjMgt_ReadData.hxx
@@ -26,7 +26,24 @@ class Standard_GUID;
 class StdObjMgt_ReadData
 {
 public:
-  class Object;
+  //! Auxiliary class used to automate begin and end of
+  //! reading object (eating opening and closing parenthesis)
+  //! at constructor and destructor
+  class ObjectSentry
+  {
+  public:
+    explicit ObjectSentry (StdObjMgt_ReadData& theData) : myReadData (&theData)
+    { myReadData->myDriver->BeginReadObjectData(); }
+
+    ~ObjectSentry ()
+    { myReadData->myDriver->EndReadObjectData(); }
+
+  private:
+    StdObjMgt_ReadData* myReadData;
+
+    ObjectSentry (const ObjectSentry&);
+    ObjectSentry& operator = (const ObjectSentry&);
+  };
 
   Standard_EXPORT StdObjMgt_ReadData
     (Storage_BaseDriver& theDriver, const Standard_Integer theNumberOfObjects);
@@ -88,31 +105,7 @@ private:
   NCollection_Array1<Handle(StdObjMgt_Persistent)> myPersistentObjects;
 };
 
-class StdObjMgt_ReadData::Object
-{
-public:
-  Object (StdObjMgt_ReadData& theData) : myReadData (&theData)
-    { myReadData->myDriver->BeginReadObjectData(); }
-  Object(const StdObjMgt_ReadData::Object& theOther) : myReadData(theOther.myReadData)
-    { myReadData->myDriver->BeginReadObjectData(); }
-
-  ~Object()
-    { myReadData->myDriver->EndReadObjectData(); }
-
-  operator StdObjMgt_ReadData&()
-    { return *myReadData; }
-
-  template <class Data>
-  StdObjMgt_ReadData& operator >> (Data& theData)
-    { return *myReadData >> theData; }
-
-private:
-  StdObjMgt_ReadData* myReadData;
-
-  StdObjMgt_ReadData::Object& operator = (const StdObjMgt_ReadData::Object&);
-};
-
 Standard_EXPORT StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, Standard_GUID& theGUID);
+  (StdObjMgt_ReadData& theReadData, Standard_GUID& theGUID);
 
 #endif // _StdObjMgt_ReadData_HeaderFile
diff --git a/src/StdObjMgt/StdObjMgt_WriteData.cxx b/src/StdObjMgt/StdObjMgt_WriteData.cxx
index cbd9b4fb87..7830181f26 100644
--- a/src/StdObjMgt/StdObjMgt_WriteData.cxx
+++ b/src/StdObjMgt/StdObjMgt_WriteData.cxx
@@ -44,8 +44,10 @@ StdObjMgt_WriteData& StdObjMgt_WriteData::operator << (const Handle(StdObjMgt_Pe
 //purpose  : Read persistent data from a file
 //=======================================================================
 StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const Standard_GUID& theGUID)
+  (StdObjMgt_WriteData& theWriteData, const Standard_GUID& theGUID)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   const Standard_UUID anUUID = theGUID.ToUUID();
 
   Standard_Integer      a32b;
diff --git a/src/StdObjMgt/StdObjMgt_WriteData.hxx b/src/StdObjMgt/StdObjMgt_WriteData.hxx
index 48d5ea4b19..22b97c97f1 100644
--- a/src/StdObjMgt/StdObjMgt_WriteData.hxx
+++ b/src/StdObjMgt/StdObjMgt_WriteData.hxx
@@ -25,7 +25,24 @@ class StdObjMgt_WriteData
 {
 public:
 
-  class Object;
+  //! Auxiliary class used to automate begin and end of
+  //! writing object (adding opening and closing parenthesis)
+  //! at constructor and destructor
+  class ObjectSentry
+  {
+  public:
+    explicit ObjectSentry (StdObjMgt_WriteData& theData) : myWriteData(&theData)
+    { myWriteData->myDriver->BeginWriteObjectData(); }
+
+    ~ObjectSentry()
+    { myWriteData->myDriver->EndWriteObjectData(); }
+
+  private:
+    StdObjMgt_WriteData* myWriteData;
+
+    ObjectSentry (const ObjectSentry&);
+    ObjectSentry& operator = (const ObjectSentry&);
+  };
 
   Standard_EXPORT StdObjMgt_WriteData 
     (Storage_BaseDriver& theDriver);
@@ -71,31 +88,7 @@ private:
   Storage_BaseDriver* myDriver;
 };
 
-class StdObjMgt_WriteData::Object
-{
-public:
-  Object (StdObjMgt_WriteData& theData) : myWriteData(&theData)
-    { myWriteData->myDriver->BeginWriteObjectData(); }
-  Object (const StdObjMgt_WriteData::Object& theOther) : myWriteData(theOther.myWriteData)
-    { myWriteData->myDriver->BeginWriteObjectData(); }
-
-  ~Object()
-    { myWriteData->myDriver->EndWriteObjectData(); }
-
-  operator StdObjMgt_WriteData& ()
-    { return *myWriteData; }
-
-  template <class Data>
-  StdObjMgt_WriteData& operator << (Data& theData)
-    { return *myWriteData << theData; }
-
-private:
-  StdObjMgt_WriteData* myWriteData;
-
-  StdObjMgt_WriteData::Object& operator = (const StdObjMgt_WriteData::Object&);
-};
-
 Standard_EXPORT StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const Standard_GUID& theGUID);
+  (StdObjMgt_WriteData& theWriteData, const Standard_GUID& theGUID);
 
 #endif // _StdObjMgt_WriteData_HeaderFile
diff --git a/src/StdObject/StdObject_Location.hxx b/src/StdObject/StdObject_Location.hxx
index 29a0854277..7c729d4d48 100644
--- a/src/StdObject/StdObject_Location.hxx
+++ b/src/StdObject/StdObject_Location.hxx
@@ -40,22 +40,24 @@ private:
   Handle(StdObjMgt_Persistent) myData;
 
   friend StdObjMgt_ReadData& operator >>
-    (StdObjMgt_ReadData::Object, StdObject_Location&);
+    (StdObjMgt_ReadData&, StdObject_Location&);
   friend StdObjMgt_WriteData& operator <<
-    (StdObjMgt_WriteData::Object, const StdObject_Location&);
+    (StdObjMgt_WriteData&, const StdObject_Location&);
 };
 
 //! Read persistent data from a file.
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, StdObject_Location& theLocation)
+  (StdObjMgt_ReadData& theReadData, StdObject_Location& theLocation)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
   return theReadData >> theLocation.myData;
 }
 
 //! Write persistent data to a file.
 inline StdObjMgt_WriteData& operator <<
-(StdObjMgt_WriteData::Object theWriteData, const StdObject_Location& theLocation)
+  (StdObjMgt_WriteData& theWriteData, const StdObject_Location& theLocation)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
   return theWriteData << theLocation.myData;
 }
 
diff --git a/src/StdObject/StdObject_Shape.hxx b/src/StdObject/StdObject_Shape.hxx
index 58d0111412..7d1ab803e5 100644
--- a/src/StdObject/StdObject_Shape.hxx
+++ b/src/StdObject/StdObject_Shape.hxx
@@ -48,23 +48,25 @@ protected:
   Standard_Integer                     myOrient;
 
   friend StdObjMgt_ReadData& operator >>
-    (StdObjMgt_ReadData::Object, StdObject_Shape&);
+    (StdObjMgt_ReadData&, StdObject_Shape&);
   friend StdObjMgt_WriteData& operator <<
-    (StdObjMgt_WriteData::Object, const StdObject_Shape&);
+    (StdObjMgt_WriteData&, const StdObject_Shape&);
 };
 
 //! Read persistent data from a file.
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, StdObject_Shape& theShape)
+  (StdObjMgt_ReadData& theReadData, StdObject_Shape& theShape)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
   theShape.read (theReadData);
   return theReadData;
 }
 
 //! Write persistent data to a file.
 inline StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const StdObject_Shape& theShape)
+  (StdObjMgt_WriteData& theWriteData, const StdObject_Shape& theShape)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
   theShape.write (theWriteData);
   return theWriteData;
 }
diff --git a/src/StdObject/StdObject_gp_Axes.hxx b/src/StdObject/StdObject_gp_Axes.hxx
index f5c78bc335..105487e24e 100644
--- a/src/StdObject/StdObject_gp_Axes.hxx
+++ b/src/StdObject/StdObject_gp_Axes.hxx
@@ -26,8 +26,9 @@
 
 
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, gp_Ax2d& theAx)
+  (StdObjMgt_ReadData& theReadData, gp_Ax2d& theAx)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
   gp_Pnt2d aLoc;
   gp_Dir2d aDir;
   theReadData >> aLoc >> aDir;
@@ -36,8 +37,10 @@ inline StdObjMgt_ReadData& operator >>
 }
 
 inline StdObjMgt_WriteData& 
-  write (StdObjMgt_WriteData::Object theWriteData, const gp_Ax2d& theAx)
+  write (StdObjMgt_WriteData& theWriteData, const gp_Ax2d& theAx)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   const gp_Pnt2d& aLoc = theAx.Location();
   const gp_Dir2d& aDir = theAx.Direction();
   theWriteData << aLoc << aDir;
@@ -45,8 +48,10 @@ inline StdObjMgt_WriteData&
 }
 
 inline StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const gp_Ax2d& theAx)
+  (StdObjMgt_WriteData& theWriteData, const gp_Ax2d& theAx)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   const gp_Pnt2d& aLoc = theAx.Location();
   const gp_Dir2d& aDir = theAx.Direction();
   theWriteData << aLoc << aDir;
@@ -54,8 +59,9 @@ inline StdObjMgt_WriteData& operator <<
 }
 
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, gp_Ax22d& theAx)
+  (StdObjMgt_ReadData& theReadData, gp_Ax22d& theAx)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
   gp_Pnt2d aLoc;
   gp_Dir2d aYDir, aXDir;
   theReadData >> aLoc >> aYDir >> aXDir;
@@ -64,8 +70,10 @@ inline StdObjMgt_ReadData& operator >>
 }
 
 inline StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const gp_Ax22d& theAx)
+  (StdObjMgt_WriteData& theWriteData, const gp_Ax22d& theAx)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   const gp_Pnt2d& aLoc = theAx.Location();
   const gp_Dir2d& aYDir = theAx.YDirection();
   const gp_Dir2d& aXDir = theAx.XDirection();
@@ -74,8 +82,9 @@ inline StdObjMgt_WriteData& operator <<
 }
 
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, gp_Ax1& theAx)
+  (StdObjMgt_ReadData& theReadData, gp_Ax1& theAx)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
   gp_Pnt aLoc;
   gp_Dir aDir;
   theReadData >> aLoc >> aDir;
@@ -84,8 +93,10 @@ inline StdObjMgt_ReadData& operator >>
 }
 
 inline StdObjMgt_WriteData&
-  write(StdObjMgt_WriteData::Object theWriteData, const gp_Ax1& theAx)
+  write(StdObjMgt_WriteData& theWriteData, const gp_Ax1& theAx)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   const gp_Pnt& aLoc = theAx.Location();
   const gp_Dir& aDir = theAx.Direction();
   theWriteData << aLoc << aDir;
@@ -93,8 +104,10 @@ inline StdObjMgt_WriteData&
 }
 
 inline StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const gp_Ax1& theAx)
+  (StdObjMgt_WriteData& theWriteData, const gp_Ax1& theAx)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   const gp_Pnt& aLoc = theAx.Location();
   const gp_Dir& aDir = theAx.Direction();
   theWriteData << aLoc << aDir;
@@ -102,8 +115,9 @@ inline StdObjMgt_WriteData& operator <<
 }
 
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, gp_Ax2& theAx)
+  (StdObjMgt_ReadData& theReadData, gp_Ax2& theAx)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
   gp_Ax1 anAx;
   gp_Dir aYDir, aXDir;
   theReadData >> anAx >> aYDir >> aXDir;
@@ -112,8 +126,10 @@ inline StdObjMgt_ReadData& operator >>
 }
 
 inline StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const gp_Ax2& theAx)
+  (StdObjMgt_WriteData& theWriteData, const gp_Ax2& theAx)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   const gp_Ax1& anAx = theAx.Axis();
   const gp_Dir& aYDir = theAx.YDirection();
   const gp_Dir& aXDir = theAx.XDirection();
@@ -122,8 +138,9 @@ inline StdObjMgt_WriteData& operator <<
 }
 
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, gp_Ax3& theAx)
+  (StdObjMgt_ReadData& theReadData, gp_Ax3& theAx)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
   gp_Ax1 anAx;
   gp_Dir aYDir, aXDir;
   theReadData >> anAx >> aYDir >> aXDir;
@@ -134,8 +151,10 @@ inline StdObjMgt_ReadData& operator >>
 }
 
 inline StdObjMgt_WriteData& operator <<
-(StdObjMgt_WriteData::Object theWriteData, const gp_Ax3& theAx)
+  (StdObjMgt_WriteData& theWriteData, const gp_Ax3& theAx)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   const gp_Ax1& anAx = theAx.Axis();
   const gp_Dir& aYDir = theAx.YDirection();
   const gp_Dir& aXDir = theAx.XDirection();
diff --git a/src/StdObject/StdObject_gp_Trsfs.hxx b/src/StdObject/StdObject_gp_Trsfs.hxx
index 54cc6a27cb..8d5d311d4f 100644
--- a/src/StdObject/StdObject_gp_Trsfs.hxx
+++ b/src/StdObject/StdObject_gp_Trsfs.hxx
@@ -25,8 +25,9 @@
 
 
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, gp_Mat2d& theMat)
+  (StdObjMgt_ReadData& theReadData, gp_Mat2d& theMat)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
   theReadData
     >> theMat(1, 1) >> theMat(1, 2)
     >> theMat(2, 1) >> theMat(2, 2);
@@ -34,8 +35,10 @@ inline StdObjMgt_ReadData& operator >>
 }
 
 inline StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const gp_Mat2d& theMat)
+  (StdObjMgt_WriteData& theWriteData, const gp_Mat2d& theMat)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   theWriteData
     << theMat(1, 1) << theMat(1, 2)
     << theMat(2, 1) << theMat(2, 2);
@@ -43,8 +46,9 @@ inline StdObjMgt_WriteData& operator <<
 }
 
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, gp_Mat& theMat)
+  (StdObjMgt_ReadData& theReadData, gp_Mat& theMat)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
   theReadData
     >> theMat(1, 1) >> theMat(1, 2) >> theMat(1, 3)
     >> theMat(2, 1) >> theMat(2, 2) >> theMat(2, 3)
@@ -53,8 +57,10 @@ inline StdObjMgt_ReadData& operator >>
 }
 
 inline StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const gp_Mat& theMat)
+  (StdObjMgt_WriteData& theWriteData, const gp_Mat& theMat)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   theWriteData
     << theMat(1, 1) << theMat(1, 2) << theMat(1, 3)
     << theMat(2, 1) << theMat(2, 2) << theMat(2, 3)
@@ -63,8 +69,10 @@ inline StdObjMgt_WriteData& operator <<
 }
 
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, gp_Trsf2d& theTrsf)
+  (StdObjMgt_ReadData& theReadData, gp_Trsf2d& theTrsf)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
+
   Standard_Real    aScale;
   Standard_Integer aForm;
   gp_Mat2d         aMat;
@@ -79,8 +87,10 @@ inline StdObjMgt_ReadData& operator >>
 }
 
 inline StdObjMgt_WriteData& operator <<
-(StdObjMgt_WriteData::Object theWriteData, const gp_Trsf2d& theTrsf)
+  (StdObjMgt_WriteData& theWriteData, const gp_Trsf2d& theTrsf)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   Standard_Real    aScale = theTrsf.ScaleFactor();
   Standard_Integer aForm  = theTrsf.Form();
   const gp_Mat2d&  aMat   = theTrsf.HVectorialPart();
@@ -92,8 +102,10 @@ inline StdObjMgt_WriteData& operator <<
 }
 
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, gp_Trsf& theTrsf)
+  (StdObjMgt_ReadData& theReadData, gp_Trsf& theTrsf)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
+
   Standard_Real    aScale;
   Standard_Integer aForm;
   gp_Mat           aMat;
@@ -110,8 +122,10 @@ inline StdObjMgt_ReadData& operator >>
 }
 
 inline StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const gp_Trsf& theTrsf)
+  (StdObjMgt_WriteData& theWriteData, const gp_Trsf& theTrsf)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   Standard_Real    aScale = theTrsf.ScaleFactor();
   Standard_Integer aForm  = theTrsf.Form();
   const gp_Mat&    aMat   = theTrsf.HVectorialPart();
diff --git a/src/StdObject/StdObject_gp_Vectors.hxx b/src/StdObject/StdObject_gp_Vectors.hxx
index 4090a25cc7..66b28f0b77 100644
--- a/src/StdObject/StdObject_gp_Vectors.hxx
+++ b/src/StdObject/StdObject_gp_Vectors.hxx
@@ -28,8 +28,10 @@
 
 
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, gp_XY& theXY)
+  (StdObjMgt_ReadData& theReadData, gp_XY& theXY)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
+
   Standard_Real aX, aY;
   theReadData >> aX >> aY;
   theXY.SetCoord (aX, aY);
@@ -37,16 +39,20 @@ inline StdObjMgt_ReadData& operator >>
 }
 
 inline StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const gp_XY& theXY)
+  (StdObjMgt_WriteData& theWriteData, const gp_XY& theXY)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   Standard_Real aX = theXY.X(), aY = theXY.Y();
   theWriteData << aX << aY;
   return theWriteData;
 }
 
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, gp_Pnt2d& thePnt)
+  (StdObjMgt_ReadData& theReadData, gp_Pnt2d& thePnt)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
+
   gp_XY aXY;
   theReadData >> aXY;
   thePnt.SetXY (aXY);
@@ -54,15 +60,19 @@ inline StdObjMgt_ReadData& operator >>
 }
 
 inline StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const gp_Pnt2d& thePnt)
+  (StdObjMgt_WriteData& theWriteData, const gp_Pnt2d& thePnt)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   theWriteData << thePnt.XY();
   return theWriteData;
 }
 
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, gp_Vec2d& theVec)
+  (StdObjMgt_ReadData& theReadData, gp_Vec2d& theVec)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
+
   gp_XY aXY;
   theReadData >> aXY;
   theVec.SetXY (aXY);
@@ -70,15 +80,19 @@ inline StdObjMgt_ReadData& operator >>
 }
 
 inline StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const gp_Vec2d& theVec)
+  (StdObjMgt_WriteData& theWriteData, const gp_Vec2d& theVec)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   theWriteData << theVec.XY();
   return theWriteData;
 }
 
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, gp_Dir2d& theDir)
+  (StdObjMgt_ReadData& theReadData, gp_Dir2d& theDir)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
+
   gp_XY aXY;
   theReadData >> aXY;
   theDir.SetXY (aXY);
@@ -86,15 +100,19 @@ inline StdObjMgt_ReadData& operator >>
 }
 
 inline StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const gp_Dir2d& theDir)
+  (StdObjMgt_WriteData& theWriteData, const gp_Dir2d& theDir)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   theWriteData << theDir.XY();
   return theWriteData;
 }
 
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, gp_XYZ& theXYZ)
+  (StdObjMgt_ReadData& theReadData, gp_XYZ& theXYZ)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
+
   Standard_Real aX, aY, aZ;
   theReadData >> aX >> aY >> aZ;
   theXYZ.SetCoord(aX, aY, aZ);
@@ -102,16 +120,20 @@ inline StdObjMgt_ReadData& operator >>
 }
 
 inline StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const gp_XYZ& theXYZ)
+  (StdObjMgt_WriteData& theWriteData, const gp_XYZ& theXYZ)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   Standard_Real aX = theXYZ.X(), aY = theXYZ.Y(), aZ = theXYZ.Z();
   theWriteData << aX << aY << aZ;
   return theWriteData;
 }
 
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, gp_Pnt& thePnt)
+  (StdObjMgt_ReadData& theReadData, gp_Pnt& thePnt)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
+
   gp_XYZ aXYZ;
   theReadData >> aXYZ;
   thePnt.SetXYZ (aXYZ);
@@ -119,15 +141,19 @@ inline StdObjMgt_ReadData& operator >>
 }
 
 inline StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const gp_Pnt& thePnt)
+  (StdObjMgt_WriteData& theWriteData, const gp_Pnt& thePnt)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   theWriteData << thePnt.XYZ();
   return theWriteData;
 }
 
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, gp_Vec& theVec)
+  (StdObjMgt_ReadData& theReadData, gp_Vec& theVec)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
+
   gp_XYZ aXYZ;
   theReadData >> aXYZ;
   theVec.SetXYZ (aXYZ);
@@ -135,15 +161,19 @@ inline StdObjMgt_ReadData& operator >>
 }
 
 inline StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const gp_Vec& theVec)
+  (StdObjMgt_WriteData& theWriteData, const gp_Vec& theVec)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   theWriteData << theVec.XYZ();
   return theWriteData;
 }
 
 inline StdObjMgt_ReadData& operator >>
-  (StdObjMgt_ReadData::Object theReadData, gp_Dir& theDir)
+  (StdObjMgt_ReadData& theReadData, gp_Dir& theDir)
 {
+  StdObjMgt_ReadData::ObjectSentry aSentry (theReadData);
+
   gp_XYZ aXYZ;
   theReadData >> aXYZ;
   theDir.SetXYZ(aXYZ);
@@ -151,8 +181,10 @@ inline StdObjMgt_ReadData& operator >>
 }
 
 inline StdObjMgt_WriteData& operator <<
-  (StdObjMgt_WriteData::Object theWriteData, const gp_Dir& theDir)
+  (StdObjMgt_WriteData& theWriteData, const gp_Dir& theDir)
 {
+  StdObjMgt_WriteData::ObjectSentry aSentry (theWriteData);
+
   theWriteData << theDir.XYZ();
   return theWriteData;
 }
diff --git a/tests/bugs/fclasses/begin b/tests/bugs/fclasses/begin
index 5fee6fb13b..6b038e8401 100755
--- a/tests/bugs/fclasses/begin
+++ b/tests/bugs/fclasses/begin
@@ -1,9 +1 @@
 set subgroup fclasses
-
-
-
-
-
-
-
-
diff --git a/tests/bugs/fclasses/bug29355 b/tests/bugs/fclasses/bug29355
new file mode 100644
index 0000000000..88b5a800b5
--- /dev/null
+++ b/tests/bugs/fclasses/bug29355
@@ -0,0 +1,16 @@
+puts "# ======================================================================"
+puts "# 0029355: OCCT 6.9.1 persistence restored in OCCT 7.2.0 not working"
+puts "# ======================================================================"
+
+pload OCAF MODELING
+
+puts ""
+puts "# Check reading of shape from FSD archive"
+fsdread [locate_data_file bug29355.fsd] a
+checkshape a
+checknbshapes a -face 14 -solid 0 -edge 39 -vertex 26
+
+puts ""
+puts "# Check that reading fails with expected message on truncated file"
+puts "REQUIRED 29355 ALL: Error : 6"
+catch {fsdread [locate_data_file bug29355_truncated.fsd] a}