Hi Cetin ,thanks for the feed back...

I suppose any application (exe) returns an exitcode when terminate normally or even anormally.
trapping that exicode can inform the user of its successfull or insuccessfull end.
its the same with APIs result...
When a program exits, it is common to return an integer value to indicate the closing state.
If the program closed normally, this value is generally zero. Other values usually provide error
codes that allow the caller to identify problems.