[Boost-users] [shared_ptr] Error in Constructor

Using boost 1.42, the attached fails to compile with g++: shared_ptr_test.cpp: In instantiation of ‘Wrapper<A>’: /usr/include/boost/smart_ptr/detail/sp_convertible.hpp:48: instantiated from ‘boost::detail::sp_convertible’ /usr/include/boost/smart_ptr/detail/sp_convertible.hpp:67: instantiated from ‘boost::detail::sp_enable_if_convertible’ shared_ptr_test.cpp:33: instantiated from here shared_ptr_test.cpp :14: error: invalid use of incomplete type ‘struct A’ shared_ptr_test.cpp:5: error: forward declaration of ‘struct A’ This is surprising to me as the code does not use A anywhere. I found BOOST_SP_NO_SP_CONVERTIBLE in shared_ptr.hpp and indeed turning that on fixes the problem. Unfortunately, it doesn't seem to be documented. What's the rationale for the enable_if'd constructor? Is BOOST_SP_NO_SP_CONVERTIBLE an official part of the library? Apparently it is causing gcc to check all doSomething members of Action against shared_ptr and those checks are causing instantiations of Wrapper<A>. -Dave