return m_file->Tell();
 }
 
-bool wxFileInputStream::IsOk() const 
-{ 
-    return (wxStreamBase::IsOk() && m_file->IsOpened()); 
+bool wxFileInputStream::IsOk() const
+{
+    return wxInputStream::IsOk() && m_file->IsOpened();
 }
 
 // ----------------------------------------------------------------------------
     return m_file->Length();
 }
 
-bool wxFileOutputStream::IsOk() const 
-{ 
-    return (wxStreamBase::IsOk() && m_file->IsOpened()); 
+bool wxFileOutputStream::IsOk() const
+{
+    return wxOutputStream::IsOk() && m_file->IsOpened();
 }
 
 // ----------------------------------------------------------------------------
     wxFileOutputStream::m_file = wxFileInputStream::m_file;
 }
 
-#endif //wxUSE_FILE
+bool wxFileStream::IsOk() const
+{
+    return wxFileOutputStream::IsOk() && wxFileInputStream::IsOk();
+}
+
+#endif // wxUSE_FILE
 
 #if wxUSE_FFILE
 
     return m_file->Tell();
 }
 
-bool wxFFileInputStream::IsOk() const 
-{ 
-    return (wxStreamBase::IsOk() && m_file->IsOpened()); 
+bool wxFFileInputStream::IsOk() const
+{
+    return wxStreamBase::IsOk() && m_file->IsOpened();
 }
 
 // ----------------------------------------------------------------------------
     return m_file->Length();
 }
 
-bool wxFFileOutputStream::IsOk() const 
-{ 
-    return (wxStreamBase::IsOk() && m_file->IsOpened()); 
+bool wxFFileOutputStream::IsOk() const
+{
+    return wxStreamBase::IsOk() && m_file->IsOpened();
 }
 
 // ----------------------------------------------------------------------------
     wxFFileOutputStream::m_file = wxFFileInputStream::m_file;
 }
 
+bool wxFFileStream::IsOk() const
+{
+    return wxFFileOutputStream::IsOk() && wxFFileInputStream::IsOk();
+}
+
 #endif //wxUSE_FFILE
 
 #endif // wxUSE_STREAMS