(Declared but not defined) Return bslmf::Tag<false>() if the first argument is an rvalue and bslmf::Tag<true>() if it is lvalue. In actual use, the second argument is always a literal int, which causes the second overload to be preferred in case of ambiguity.
Declared in <bslmf_invokeresult.h>
static
bslmf::Tag<false>
checkLvalue(/* implementation-defined */, ...);