On 09/01/2011 12:30 PM, Mathias Gaunard wrote:
On 01/09/2011 05:26, Andrey Semashev wrote:
In addition, on most platforms there will be multiple instances of type_id<T>::value for a single given T if the application uses type_id<T> in multiple modules.
That's not a problem, type_id<T>::value is a weak symbol.
It doesn't matter. I wasn't speaking of different translation units, but different modules (i.e. dll, so, dylib). Unless you do explicit exporting/importing of this symbol, you'll have separate instances.
These instances will be initialized independently and most likely will have different ids. And since next_id() is also module-private, inter-module passing of boost::any becomes totally impossible.
You could make next_id a function with weak extern linkage, which should be able to make it work.
The problem is not with the function itself but rather its local static variable, which is subject to the same issues as with type_id<T>::value.