Trying to save and load a CMap. I thought I could just call the SerializeElements. But everybody seams to overload the SerializeElements why is that necsesary? I have not seen one single example of a call to the function.
SerializeElements takes the size of the CMap as input argument. But how do I know the size of the CMap when I load a CMap from a file?

void CGsdoc_b1Doc::Serialize(CArchive& ar)
int size = m_UserMap.GetCount();
if (ar.IsStoring())
// TODO: add storing code here

SerializeElements ( ar, &m_UserMap , size);