Last system error message

GetSysErrorMessage.cpp

std::string GetSysErrorMessage(unsigned long errorCode)
{
   // get error message from system
   LPTSTR messageBuffer;

   if (
      ::FormatMessage(
         FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
            FORMAT_MESSAGE_IGNORE_INSERTS,
         NULL, errorCode, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
         (LPTSTR)&messageBuffer, 0, NULL) == 0)
   {
      return {};
   }

   if (messageBuffer == nullptr)
      return {};

   std::string result = messageBuffer;

   LocalFree(messageBuffer);

   return result;
}