Following the question in Heterogenous vectors of pointers. How to call functions.
I would like to know how to identify null points inside the vector of boost::variant.
Example code:
#include <boost/variant.hpp>
#include <vector>
template< typename T>
class A
{
public:
A(){}
~A(){}
void write();
private:
T data;
};
template< typename T>
void A<T>::write()
{
std::cout << data << std::endl;
}
class myVisitor
: public boost::static_visitor<>
{
public:
template< typename T>
void operator() (A<T>* a) const
{
a->write();
}
};
int main()
{
A<int> one;
A<double> two;
typedef boost::variant<A<int>*, A<double>* > registry;
std::vector<registry> v;
v.push_back(&one);
v.push_back(&two);
A<int>* tst = new A<int>;
for(auto x: v)
{
boost::apply_visitor(myVisitor(), x);
try {delete tst; tst = nullptr;}
catch (...){}
}
}
Since I am deleting the pointer I would hope that the last one will give me an error or something. How can I check if the entry in the entry is pointing to nullptr?
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