CODEWITHSUNDEEP
c++visual-c++mfc
PortMan
PortMan

Reputation: 4523

Unable to return CMap

Using Visual Studio 2012, the following compiles:

void Stuff()
{
  CMap <int, int, int, int > myMap;
}

But when I try to return such a CMap, like this:

CMap<int, int, int, int> GetEncodingMap()
{
  CMap <int, int, int, int> encodingMap;
  return encodingMap;
}

I get the following compile error:

1>          c:\program files (x86)\microsoft visual studio 11.0\vc\atlmfc\include\afx.h(559) : see declaration of 'CObject::CObject'
1>          c:\program files (x86)\microsoft visual studio 11.0\vc\atlmfc\include\afx.h(534) : see declaration of 'CObject'
1>          This diagnostic occurred in the compiler generated function 'CMap<KEY,ARG_KEY,VALUE,ARG_VALUE>::CMap(const CMap<KEY,ARG_KEY,VALUE,ARG_VALUE> &)'
1>          with
1>          [
1>              KEY=int,
1>              ARG_KEY=int,
1>              VALUE=int,
1>              ARG_VALUE=int
1>          ]

This seems to always be the case, no matter what types I use in the CMap.

Could somebody help me understand what his happening? Is it ever possible to return a CMap from a function?

Upvotes: 0

Views: 500

Answers (3)

Ferit
Ferit

Reputation: 9707

GetEncodingMap() method doesn't create an object, just declaring and returning. Try creating before returning.

Upvotes: 0

Mgetz
Mgetz

Reputation: 5138

CMap is a non-copyable object, as it inherits from CObject which has a private copy constructor. If you want to make it copyable, you will need to inherit from CMap and provide your own, although I'm not sure how viable that is.

Upvotes: 2

Dialecticus
Dialecticus

Reputation: 16759

This is just a convoluted way of MFC trying to prevent you from copying CMap object. You can't copy a CMap object.

Upvotes: 0

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