Re: [Boost-users] [any] Is it possible to support polymorphism in boost::any?

I had exactly the same problem with some code of mine. The code was a factory like this typedef Factory > Factory_t; I wanted to store objects derived from a class (in this case, but I also wanted to support types not rooted in the same object hierarchy) and I was surprised that it failed. I think the right thing would do to work under these assumptions as well. 2010/9/6 Tang Jiang Jun :

Hello, It seems that boost::any does not support polymorphism in the following sample. class A {}; class B : public A {}; void foo( boost::any& _any ) { try { A* p = any_cast< A* >( _any );  <-- Only succeed when _any contain a pointer to a object that is exactly class A, but not any object that is descendant of class A, like B. do_some_thing( p ); } catch( const bad_any_cast& ) { } } void goo() { A* pa = new B; boost::any a = pa; foo( a ); } Is it possible to make it support this polymorphism usage? Because boost::any is a type-safe replacement of void*, I hope that boost::any has the same polymorphic behavior as void*. Regards, Tang Jiang Jun

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