is back_insert_iterator<> safe to be passed by value?
- by afriza
I have a code that looks something like:
struct Data { int value; };
class A {
public:
typedef std::deque<boost::shared_ptr<Data> > TList;
std::back_insert_iterator<TList> GetInserter()
{
return std::back_inserter(m_List);
}
private:
TList m_List;
};
class AA {
boost::scoped_ptr<A> m_a;
public:
AA() : m_a(new A()) {}
std::back_insert_iterator<A::TList> GetDataInserter()
{
return m_a->GetInserter();
}
};
class B {
template<class OutIt>
CopyInterestingDataTo(OutIt outIt)
{
// loop and check conditions for interesting data
// for every `it` in a Container<Data*>
// create a copy and store it
for( ... it = ..; .. ; ..) if (...) {
*outIt = OutIt::container_type::value_type(new Data(**it));
outIt++; // dummy
}
}
void func()
{
AA aa;
CopyInterestingDataTo(aa.GetInserter());
// aa.m_a->m_List is empty!
}
};
The problem is that A::m_List is always empty even after CopyInterestingDataTo() is called. However, if I debug and step into CopyInterestingDataTo(), the iterator does store the supposedly inserted data!
