Hallo Nicola,
Hallo, unfortunately the recently committed changes to Boost.Optional uncover a bug in BCB6, i.e. borland 5.6.4 . As 1.34 is going to be the last Boost release to officially support this compiler, it would be very important to fix this problem before the release.
What a compiler error o) I'm glad you uncover it.
The only workaround I was able to find is to revert to the previous implementation of boost/none.hpp, as in the following:
OK. That will prevent "none.hpp" and hence "optional.hpp" to be put in a precompiled header, but I guess that's better than a compiler error. If Thomas gives me a green light I'll commit it.
Given this is such a simple header it may be reasonable not to include boost/detail/workaround.hpp here and explicitly state the condition.
I like the macro better since it follows the BOOST_STRICT_CONFIG alternative.
Note that this problem is not present in borland 5.8.2.
OK Thank you for the patch. Best Fernando