On 09/01/2011 05:26 AM, Emil Dotchevski wrote:
On Wed, Aug 31, 2011 at 5:55 PM, Ilya Bobir<ilya.bobir@gmail.com> wrote:
On Wed, Aug 31, 2011 at 5:16 PM, Martin Bidlingmaier <Martin.Bidlingmaier@gmx.de> wrote:
Hi,
[...] It does not depend on rtti and uses a static integer value instead of std::type_info to store type information. [...]
Quote from any.hpp:
//use static class member to force initialization at program start to make type_id thread safe (and more efficient) template< class T> class type_id { public: static unsigned int value; }; template< class T> unsigned int type_id< T>::value = next_id();
I do not think you can initialize a class static in a header. If you include any.hpp in more than one cpp you will have the same static been initialized more than once. MS C++ linker complains. Though the standard requires no diagnostic. See "9.4.2 Static data members" paragraph 5.
In addition, in general, the initialization of statics and globals may be postponed until after main() is entered.
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. 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.