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boost::visit_each — Allow limited exploration of class members.
template<typename Visitor, typename T> void visit_each(const Visitor& visitor, const T& t, int );
The visit_each mechanism
allows a visitor to be applied to every subobject in a given
object. It is used by the Signals library to discover
signals::trackable objects within a
function object, but other uses may surface if used
universally (e.g., conservative garbage collection). To fit
within the visit_each framework,
a visit_each overload must be
supplied for each object type.
Effects:
visitor(t), and for
every subobject x of
t:
If x is a reference, visit_each(visitor, ref(x), 0)
Otherwise, visit_each(visitor, x, 0)
long for the fallback version
of visit_each and the argument
supplied to this third paramter must always be 0. The third
parameter is an artifact of the widespread lack of proper
function template ordering, and will be removed in the future.Library authors will be expected to add additional overloads that specialize the T argument for their classes, so that subobjects can be visited.
Calls to visit_each are required to be unqualified, to enable argument-dependent lookup.
| Copyright © 2001-2004 Douglas Gregor |