Re: [Boost-users] Pairing ptr_containers with zip iterators

18 Feb 2008

      Charles Brockman skrev:
...
Thorsten Ottosen wrote:
...
There are some minor differences between std::map and
boost::ptr_map and if this the types that gives you errors, it
might be due to these differences.
For example, boost::ptr_map:::value_type is not a
std::pair.
There are also some difference in the way constness is handled, which
might also be the source of your problem. Anyway, I would like to
know more.
I constructed this short do-nothing program, zip_ptr_container_test.cpp.
//
#include 
#include 
#include <map>
#include 
using boost::zip_iterator;
using boost::tuple;
using boost::make_tuple;
using boost::ptr_map;
using std::map;
int main() {
  //typedef map theMapType;
  typedef boost::ptr_map theMapType;
  typedef zip_iterator
      > zipIter;
  theMapType map1;
  theMapType map2;
  zipIter(make_tuple(map1.begin(), map2.begin()));
}
[snip]
Are these problems correctable?
I can't figure out where the error is from that. Gcc also fails to 
compile it, which is good.

I don't understand the metaprogramming machinery that boost.iterator is 
doing here, but apparently my implementation of ptr_map's iterators 
somehow violate a requirement.

-Thorsten