On Wed, May 19, 2010 at 9:55 AM, Stewart, Robert <Robert.Stewart@sig.com> wrote:
Beman Dawes wrote:
On Thu, May 6, 2010 at 12:42 PM, Jürgen Hunold <juergen.hunold@ivembh.de> wrote:
The patch introduces two Boost.Config macros - BOOST_SYMBOL_EXPORT - BOOST_SYMBOL_IMPORT
AFAICT, a third macro is needed for GCC. I've named it BOOST_SYMBOL_VISIBLE and define it as __attribute__((visibility("default")))
The need for this macro arises in header only classes like this:
class BOOST_SYMBOL_VISIBLE my_exception : public std::runtime_error { ... };
If you use BOOST_SYMBOL_EXPORT, VC++ will warn because __declspec(dllexport) isn't valid in this context.
I don't understand the problem in that case. I mark classes with __declspec(dllexport). Is it that VC's linker notices that there are no symbols in the DLL for a header-only class and complains?
At the least, you this warning: c:\boost\trunk\boost\system\system_error.hpp(26) : warning C4275: non dll-interface class 'std::runtime_error' used as base for dll-interface class 'boost::system::system_error' But for one of the Boost.System tests, VC++ gets so confused that it fails to inline the functions defined in the class, and you get a bunch of unresolved externals. --Beman