Get CString object from GetLastError information

Example.cpp

#include "stdafx.h"
#include "CGetLastError.h"

void main()
{
  // snip
  SetLastError(111);  // create a error 111 (ERROR_BUFFER_OVERFLOW) for demo
  
  // Message Box with a text associated to 111(ERROR_BUFFER_OVERFLOW) appears.
  // In English: "The file name is too long."
  // In Japanese: "ファイル名が長すぎます。"
  MessageBox(GetLastErrorToString());
  // snip
  
  SetLastError(111);  // create a error 111 (ERROR_BUFFER_OVERFLOW) for demo
  // Show error message in output window of Visual Studio
  GetLastErrorToString().CreateMsg();
}

GetLastErrorToString.cpp

#include "pch.h"	// enable for visual studio version >= 2019
// #include "stdafx.h"	// enable for visual studio version < 2019
#include "GetLastErrorToString.h"

GetLastErrorToString::operator CString()
{
	CreateMsg();
	return m_msg;
}

GetLastErrorToString::operator LPCTSTR()
{
	CreateMsg();
	return (LPCTSTR)m_msg;
}

void GetLastErrorToString::CreateMsg()
{
	LPTSTR *buff;
	m_ID = GetLastError();
	FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, m_ID, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR)&buff, 10, NULL);
	m_msg.Format(_T("%s"), buff);
	LocalFree(buff);
#ifdef UNICODE
	_RPTW2(_CRT_WARN, _T("Error ID: %d Msg: %s"), m_ID, m_msg);
#else
	_RPT2(_CRT_WARN, _T("Error ID: %d Msg: %s"), m_ID, m_msg);
#endif
}

GetLastErrorToString.h

#pragma once
class GetLastErrorToString
{
public:
	operator CString();
	operator LPCTSTR();	///	<summery>Returns temporary address of message. DO NOT USE FOR LONG TIME, OR COPY DATA IMMEDIATELY.</summery>
	void CreateMsg();
private:
	CString m_msg;
	DWORD m_ID;
};