Boost C++ Libraries: Ticket #6688: better support for exporting symbols from DLL

attachment set

arvid@… — Thu, 15 Mar 2012 05:54:47 GMT

attachment → export_symbols.diff

patch to support exporting symbols in compilers other than msvc

arvid@… — Sun, 18 Mar 2012 23:15:59 GMT

actually. with some more testing on darwin, it turns out there's one more change for this to work with GCC. the io_service::service type is not exported, only some of its member functions. My understanding of MSVC's export semantics is that all type metadata (specifically type_info and vtables) are always exported, whereas on GCC, you have to explicitly export a type for its metadata to be exported. I think the io_service::service type should be exported for this reason (otherwise I get a link error failing to find its type_info, presumably originating from a typeid() call inside an asio header).

I'm attaching an updated patch.

attachment set

arvid@… — Sun, 18 Mar 2012 23:16:56 GMT

attachment → asio_export.diff

updated patch to also export io_service::service

arvid@… — Mon, 19 Mar 2012 03:52:41 GMT

for reference, this is the error message I get if I don't export io_service::service

Undefined symbols for architecture x86_64:
  "typeinfo for boost::asio::io_service::service", referenced from:
      typeinfo for boost::asio::detail::service_base<boost::asio::socket_acceptor_service<boost::asio::ip::tcp> >in setup_transfer.o
      typeinfo for boost::asio::detail::service_base<boost::asio::deadline_timer_service<libtorrent::ptime, boost::asio::time_traits<libtorrent::ptime> > >in setup_transfer.o
ld: symbol(s) not found for architecture x86_64