Matthew Vogt wrote:

The following simple base class implements the mechanism as dicussed on Stroustrup's FAQ page, and encapsulates the virtual inheritance so that the class can be non-virtually inherited, removing the most obvious chance of implementation error.

Will this code work on multiple platforms? I have only tested on gcc 3.2... [snip]

I have tested on MS VC 6.0 sp5, 7.0 and 7.1 without any problems. On Borland 5.5.1 however, I am getting the following errors (tested in my errorcheck component): [log] Error E2404 d:\devel\adl++\include\boost/errorcheck.hpp 23: Dependent type qualifier 'boost::detail::nonderivable_base<boost::errorcheck<boost::policy::error_storage<int>,boost::policy::no_errormsg_storage>

' has no member type named 'identity' in function main()

Error E2061 d:\devel\adl++\include\boost/errorcheck.hpp 23: Friends must be functions or classes in function main() Error E2029 d:\devel\adl++\include\boost/errorcheck.hpp 33: 'boost::detail::nonderivable_base<boost::errorcheck<boost::policy::error_storage<int>,boost::policy::no_errormsg_storage>

' must be a previously defined class or struct in function main()

Error E2029 d:\devel\adl++\include\boost/errorcheck.hpp 136: 'boost::nonderivable<boost::errorcheck<boost::policy::error_storage<int>,boost::policy::no_errormsg_storage>

' must be a previously defined class or struct in function main()

[/log] I don't have any workarounds at present. Regards, Reece _________________________________________________________________ Sign-up for a FREE BT Broadband connection today! http://www.msn.co.uk/specials/btbroadband