For win32 implementation exception contains windows get last error rather that
for unix-like implementation. It would be good add (for example) last error to
exception for unix-like implementation. For example SharedSemaphore has two
implementation: for win32 and others. 

Win32 implementation:
                void SharedSemaphore::createHandle() {
....
                        if (!m_hSemaphore){
                                throw SystemException ( 
                                        boost::format( "Unable to create a
shared semaphore '%1%': %2%") %m_nId %getLastWindowsError()
                                );
                        }
                }

Unix-like implementations
                void SharedSemaphore::createHandle() {
....
                        if (m_hSemaphore == -1){
                                throw SystemException ( 
                                        boost::format( "Unable to create a
shared semaphore '%1%'") %m_nId
                                );
                        }
                }

Portable getLastOSErrorString() (instead getLastWindowsError()) has been added.