The C++98-style concept check for output iterators causes a link
failure on mingw-w64, because the __val() member function isn't defined.
Change it to use a function pointer instead. That pointer is never set
to anything meaningful, but it doesn't matter as the __constraints()
function only has to be instantiated, it's never called.
We could refactor all of these to use unevaluated contexts (e.g. sizeof
of __decltype) so that we only check the expressions are well-formed,
without any codegen at all. Any improvements to these are very low
priority though.
libstdc++-v3/ChangeLog:
* include/bits/boost_concept_check.h (_OutputIteratorConcept):
Change member function to data member of function pointer type.
*__i++ = __val(); // require postincrement and assignment
}
_Tp __i;
- _ValueT __val() const;
+ // Use a function pointer here so no definition of the function needed.
+ // Just need something that returns a _ValueT (which might be a reference).
+ _ValueT (*__val)();
};
template<typename _Tp>