Storing std::type_info

Hi all,

I tried to store a std::type_info value in my code so I didn't have to
call typeid more than once when checking if a polymorphic object is of
one of certain types, like this:

#include <typeinfo>

class A
{
  public:
   virtual int foo() { return 42; }
};

class B : public A
{};

class C : public A
{};

void foo(A& obj)
{
  std::type_info type(typeid(obj));

  if(type==typeid(B)) { ... }
  if(type==typeid(C)) { ... }
}

I found, however, that the copy-constructor of type_info was private; is
it save to store the value by reference:

const std::type_info& type(typeid(obj)); ?

This compiles fine, but I'm not sure whether this stores the reference
to a temporary object which is no longer valid when the comparison happens.

Is is ok to do this with references? Or is there any other way to store
the type_info or do I have to insert typeid(obj) everywhere in the ifs?

Yours,
Daniel

PS: I know that RTTI should be uses as rarly as possible, please don't
tell me I should use something else. In my real situation, I believe
RTTI similar to this is what I want.

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