return m_file->Tell();
 }
 
+bool wxFileInputStream::IsOk() const 
+{ 
+    return (wxStreamBase::IsOk() && m_file->IsOpened()); 
+}
+
 // ----------------------------------------------------------------------------
 // wxFileOutputStream
 // ----------------------------------------------------------------------------
     return m_file->Length();
 }
 
+bool wxFileOutputStream::IsOk() const 
+{ 
+    return (wxStreamBase::IsOk() && m_file->IsOpened()); 
+}
+
 // ----------------------------------------------------------------------------
 // wxTempFileOutputStream
 // ----------------------------------------------------------------------------
     return m_file->Tell();
 }
 
+bool wxFFileInputStream::IsOk() const 
+{ 
+    return (wxStreamBase::IsOk() && m_file->IsOpened()); 
+}
+
 // ----------------------------------------------------------------------------
 // wxFFileOutputStream
 // ----------------------------------------------------------------------------
     return m_file->Length();
 }
 
+bool wxFFileOutputStream::IsOk() const 
+{ 
+    return (wxStreamBase::IsOk() && m_file->IsOpened()); 
+}
+
 // ----------------------------------------------------------------------------
 // wxFFileStream
 // ----------------------------------------------------------------------------