              value                                             meaning
*IDABORT                                  Abort button was selected
*IDCANCEL                                Cancel button was selected
*IDCONTINUE                           Continue button was selected
*IDIGNORE                                 Ignore button was selected
*IDNO                                          NO button was selected
*IDOK                                          OK button was selected
*IDRETRY                                    Retry button was selected
*IDTRVAGAIN                           Try again button was selected
*IDYES                                          Yes button was selected

If the functions fails,the return zero,To get extended error information,call GetLastError