[Top-post since the new stuff gives a fuller context.] I think I need to explain things. (This is what I get for not reading Boost e-mail for a few days. I could have nipped this in the bud. I didn't find out about this problem myself until I tried a compile....) 1. <boost/utility_fwd.hpp> was introduced with <boost/utility/base_from_member.hpp> 1a. <boost/utility/base_from_member.hpp> #includes <boost/utility_fwd.hpp>, and needs to since a template value default is in the forwarding header. 2. The other forward-able items in <boost/utility.hpp> were added to <boost/utility_fwd.hpp> upon first commit. 3. The various items in <boost/utility.hpp> were split into several headers. 4. The maintainers of <boost/noncopyable.hpp>, then _and_ now, ignored the fact that <boost/utility_fwd.hpp> referenced boost::noncopyable. This was the mistake. 5. What should have happened was to add "#include <boost/utility_fwd.hpp>" to <boost/noncopyable.hpp> at the time of the split. 6. The reason for [5]? Headers that have a corresponding forwarding header should always #include that forwarding header. Why? So... 7. If someone makes a significant change in the primary header, the mismatch in the forwarding header will cause a compile-time error. (If only we caught the mistake at [4], then Dave's change would have been flagged, and we could have avoided this incident.) 8. Unfortunately, Dave and Aleksey didn't understand this and went the other way. Instead of adding "#include <boost/utility_fwd.hpp>" to <boost/noncopyable.hpp> (Bronek Kozicki suggested this), they excised boost::noncopyable from <boost/utility_fwd.hpp>. So, can we make the change go the other way? On 8/20/04 2:18 PM, "David Abrahams" <dave@boost-consulting.com> wrote:
Matthias Troyer <troyer@itp.phys.ethz.ch> writes:
Your latest changes to noncopyable (putting it into namespace noncopyable_) seem to break a lot of boost code, since class noncopyable now no longer exists in namespace boost.
It should be better now. The original problem, as Aleksey suggested, was utility_fwd.hpp, which as a matter of fact I was *not* using. I just removed the noncopyable forward declaration and typedef from it and put it all in noncopyable.hpp.
Sorry for the churn, everybody.
-- Daryle Walker Mac, Internet, and Video Game Junkie darylew AT hotmail DOT com