Re: Forward declaration in with unordered_map
eggplantparts@yahoo.com writes:
#include <tr1/unordered_map>
#include <map>
class DATA {
public:
std::map<int, DATA>::iterator a; // ok
std::tr1::unordered_map<int, DATA>::iterator b; // error
};
the map declaration compiles without err, but the unordered_map
declaration gives me a "forward declaration of 'class DATA'"
error. Is there any way to get around this?
Instantiating Standard Library templates with incomplete types as type
parameters causes the program to have undefined behavior. So both
lines are actually "error"; the difference is just whether the
compiler detects it.
I think that all correct solutations require the addition of a
redirection that allows you to use an incomplete type.
e.g.
struct position_type;
class DATA
{
public:
position_type *b;
};
struct position_type
{
std::tr1::unordered_map<int, DATA>::iterator thePos;
};
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