PVS-Studio warning V555 for KDE4

unsigned int rpp::Stream::peekLastOutput(uint backOffset) const {
  if(m_pos - backOffset > 0)
    return m_string->at(m_pos - backOffset - 1);
  return 0;
}

This suspicious code was found in KDE4 project by PVS-Studio static code analyzer.
Warning message is:
V555 The expression 'm_pos - backOffset > 0' will work as 'm_pos != backOffset'. pp-stream.cpp 225

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/