David Abrahams wrote:
"Robert Ramey" <ramey@rrsd.com> writes:
All combinations of A and T actually used - and only those combinations - are used to instantiate code.
I don't think that can be true for any reasonable definition of "used." Code in one TU can't tell what other TUs are doing, so the code is instantiated for all archives whose headers have been included. IIRC it gets around the ordering problems you were having before by doing the instantiation as the result of overload resolution on an unqualified call, which happens in phase 2 and thus doesn't depend on having seen the overload for a particular archive type before the serializable type is EXPORTed. It doesn't do any other deep magic, IIRC.
After I thought about this some more I've also come to agree with this. So the above would be better said All combinations of A and T actually used - and only those combinations - are used to instantiate code - in a transation unit with at least one function called from either directly or indirectly from main. I never really picked up on this. This is probably because all but a couple of tests to be only one module long. I suspect that were I to modify one of export tests - it would fail in release mode in one or another of the compilers. But maybe not. The inclusion of "force_include.hpp" and corresponding usage of "_export" will probably guarentee that the compiled code is never stripped. So the problem may never be manifested in such a test. question: does the CW compiler include something like "_export" in order to compile windows (or *nix?) DLLS (shared libraries)? question:what if anything does the standard say about something like "_export" which is necessary in order to communicate that the corresponding code should never be stripped? I've been under the impression that a) "_export" is not portable b) "_export" or something like is necessary to supress code stripping c) suppression of code stripping is necessary in order to make a DLL which would imply that in order to produce a DLL, a compiler must be non-conforming - or at least support non-corformant behavior. Am I missng something here? Robert Ramey