I'm not sure if this a potential bug/problem or just a benign warning, but when using the map_values range adaptor with a ptr_map container I get a warning about returning an address of a local variable. It seems benign as the expected processing happens, but this type of warning generally doesn't sound like a good thing. The following useless code will trigger it. #include <boost/ptr_container/ptr_map.hpp> #include <boost/range/algorithm.hpp> #include <boost/range/adaptors.hpp> struct sample { int value; }; typedef boost::ptr_map<int, sample> themap; int main() { themap data; int key = 5; data.insert(key, new sample); boost::for_each(data | boost::adaptors::map_values, [](sample* s) { s->value = 10; }); return 0; } I'm using Visual Studio 2017. I also have conformance mode (/permissive-) turned on for stricter language compliance in case it makes a difference. As an aside, I was a little surprised when trying out this little sample that the inclusion of the above headers is enough to require linking with the boost regex library. I figure it's probably a reference in the adaptors somewhere. It's not a big deal. These lib files are normally available anyway. -- Bill