title: Multiple CreateFileA calls return same File Handle
body: <p>I have a routine to open COM Ports using CreateFileA.
  The function is created as a DLL and I have an EXE(using VS2010) to make calls to open different COM Ports.
  An observation is that if I use the same EXE to open different ports, The File Handle Number returned is different.
  If I open multiple instances of the EXE and open different COM Ports, the File Handle Number returned is the same.
  Eg->
  1 exe is used to open COM Port 11,12,13,14 and they return File Handle Numbers - 0x200, 0x210, 0x21c, 0x220
  4 exes, each opens one COM Port, and they all return File Handle Number - 0x200.</p>
  
  <p>I would like to know if this is due to windows threading such that each instance of the exe has a separate thread and hence the same file number?
  I am not having any problem communicating with the Ports using my exe.
  Any clues understanding this will be helpful. (Another application is trying to use this DLL and is having issues with the same File Handle number being returned)</p>
  
  <p>Thanks
  Aditya</p>