Invoking correct function based on pointer

[sgrm123]

Hi,

In my application, I am using MFC CFile operations in many places(some hundreds).

For few files(whcich are created under temp folder) I need to use CMemFile(it is derived from CFile) and for few files I need to use CFile.

Now my requirement is I should not change any files in the application wherever I am calling file operations lke open read, write, seektoend...

What I need to do is I need to create wrapper class derived from CMemFile.

class CFileWrapper : public CMemFile

{

};

In this class I need to differenciate that which file operations need to be called whether CMemFile's read function or CFile's read function.

I need to add macro to define CFile as CFileWrapper.

#define CFile CFileWrapper, whereever I am using CFile objects or pointers it will call CFileWrapper class.

Now my problem is inside CFileWrapper how to differciate which functions to call CMemFile or Cfile based on pointer.

Thanks,

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