return m_file->Tell();
 }
 
+bool wxFileInputStream::IsOk() const
+{
+    return wxInputStream::IsOk() && m_file->IsOpened();
+}
+
 // ----------------------------------------------------------------------------
 // wxFileOutputStream
 // ----------------------------------------------------------------------------
     return m_file->Length();
 }
 
+bool wxFileOutputStream::IsOk() const
+{
+    return wxOutputStream::IsOk() && m_file->IsOpened();
+}
+
 // ----------------------------------------------------------------------------
 // wxTempFileOutputStream
 // ----------------------------------------------------------------------------
     wxFileOutputStream::m_file = wxFileInputStream::m_file;
 }
 
-#endif //wxUSE_FILE
+bool wxFileStream::IsOk() const
+{
+    return wxFileOutputStream::IsOk() && wxFileInputStream::IsOk();
+}
+
+#endif // wxUSE_FILE
 
 #if wxUSE_FFILE
 
 // ----------------------------------------------------------------------------
 
 wxFFileInputStream::wxFFileInputStream(const wxString& fileName,
-                                       const wxChar *mode)
+                                       const wxString& mode)
                   : wxInputStream()
 {
     m_file = new wxFFile(fileName, mode);
     return m_file->Tell();
 }
 
+bool wxFFileInputStream::IsOk() const
+{
+    return wxStreamBase::IsOk() && m_file->IsOpened();
+}
+
 // ----------------------------------------------------------------------------
 // wxFFileOutputStream
 // ----------------------------------------------------------------------------
 
 wxFFileOutputStream::wxFFileOutputStream(const wxString& fileName,
-                                         const wxChar *mode)
+                                         const wxString& mode)
 {
     m_file = new wxFFile(fileName, mode);
     m_file_destroy = true;
     return m_file->Length();
 }
 
+bool wxFFileOutputStream::IsOk() const
+{
+    return wxStreamBase::IsOk() && m_file->IsOpened();
+}
+
 // ----------------------------------------------------------------------------
 // wxFFileStream
 // ----------------------------------------------------------------------------
     wxFFileOutputStream::m_file = wxFFileInputStream::m_file;
 }
 
+bool wxFFileStream::IsOk() const
+{
+    return wxFFileOutputStream::IsOk() && wxFFileInputStream::IsOk();
+}
+
 #endif //wxUSE_FFILE
 
 #endif // wxUSE_STREAMS