Create a string with last error message

GetLastErrorStdStr.cpp

// Needs Windows constant and type definitions
#include <windows.h>
#include <string>

// Create a string with last error message
std::string GetLastErrorStdStr()
{
DWORD error = GetLastError();
  if (error)
  {
    LPVOID lpMsgBuf;
    DWORD bufLen = FormatMessage(
        FORMAT_MESSAGE_ALLOCATE_BUFFER | 
        FORMAT_MESSAGE_FROM_SYSTEM |
        FORMAT_MESSAGE_IGNORE_INSERTS,
        NULL,
        error,
        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
        (LPTSTR) &lpMsgBuf,
        0, NULL );
    if (bufLen)
    {
      LPCSTR lpMsgStr = (LPCSTR)lpMsgBuf;
      std::string result(lpMsgStr, lpMsgStr+bufLen);
      
      LocalFree(lpMsgBuf);

      return result;
    }
  }
  return std::string();
}

std::wstring GetLastErrorStdStrW()
{
  DWORD error = GetLastError();
  if (error)
  {
    LPVOID lpMsgBuf;
    DWORD bufLen = FormatMessageW(
        FORMAT_MESSAGE_ALLOCATE_BUFFER | 
        FORMAT_MESSAGE_FROM_SYSTEM |
        FORMAT_MESSAGE_IGNORE_INSERTS,
        NULL,
        error,
        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
        (LPTSTR) &lpMsgBuf,
        0, NULL );
    if (bufLen)
    {
      LPCWSTR lpMsgStr = (LPCWSTR)lpMsgBuf;
      std::wstring result(lpMsgStr, lpMsgStr+bufLen);
      
      LocalFree(lpMsgBuf);

      return result;
    }
  }
  return std::wstring();
}