问题
Is it possible to access the arguments contained in a boost::function type?
I'd like to be able to retrieve the address of the function to be called, and the values of the arguments provided for that function.
回答1:
boost::function erases the implementation type, but if you know it, you can cast to it; since boost::function are comparable by value (== !=) the information is clearly available.
It looks like (from the function_base superclass of functionN) you can get the implementation object with:
f.target<concrete_functor_type>()
Which will return NULL if you provided the wrong concrete type.
Also in function_base (probably not helpful beyond the target method above):
public: // should be protected, but GCC 2.95.3 will fail to allow access
detail::function::vtable_base* vtable;
mutable detail::function::function_buffer functor;
vtable gives you access to:
struct vtable_base
{
void (*manager)(const function_buffer& in_buffer,
function_buffer& out_buffer,
functor_manager_operation_type op);
};
which can get you the typeid of the functor:
case get_functor_type_tag:
out_buffer.type.type = &typeid(F);
out_buffer.type.const_qualified = in_buffer.obj_ref.is_const_qualified;
out_buffer.type.volatile_qualified = in_buffer.obj_ref.is_volatile_qualified;
return;
}
function_buffer (functor) is only useful for refs to function objects, bound (this is fixed) member functions ptrs, and free functions, where you haven't bound any arguments
来源:https://stackoverflow.com/questions/1395312/access-boostfunction-arguments