lib::anonymous_namespace{lazy-init.hpp} Namespace Reference

Functions
ptrdiff_t	captureRawAddrOffset (RawAddr anchor, RawAddr subject)
template<class TAR >
static TAR *	relocate (RawAddr anchor, ptrdiff_t offset)

Variables
const ptrdiff_t	FUNCTOR_PAYLOAD_OFFSET

Variable Documentation

FUNCTOR_PAYLOAD_OFFSET

const ptrdiff_t FUNCTOR_PAYLOAD_OFFSET

Initial value:

=
      []{
          size_t slot{42};
          std::function<RawAddr(void)> probe = [slot]{ return RawAddr(&slot); };
          RawAddr functor = &probe;
          RawAddr payload = probe();
          if (not util::isCloseBy(functor, payload))
            throw err::Fatal{"Unable to use lib::LazyInit because std::function does not "
                             "apply small-object optimisation with inline storage."};
          return captureRawAddrOffset (functor,payload);
        }()

implementation defined : offset of a payload placed directly into a std::function when the small object optimisation applies.

Warning

relies on implementation behaviour not guaranteed by the standard, while supported by all known implementations today. This is exploited as a trick to allow for automatic late initialisation in a situation, were a functor needs to capture references.

Definition at line 135 of file lazy-init.hpp.

Referenced by LazyInit_test::verify_triggerMechanism().