public: // for ThreadGC.
/*
GCC cannot compile code for template versions of ThreadGC::allocGuard/freeGuard,
- the compiler produces error: \91cds::gc::dhp::details::guard_data* cds::gc::dhp::details::guard::m_pGuard\92 is protected
+ the compiler produces error: 'cds::gc::dhp::details::guard_data* cds::gc::dhp::details::guard::m_pGuard' is protected
despite the fact that ThreadGC is declared as friend for guard class.
Therefore, we have to add set_guard/get_guard public functions
*/