who can explain why exit,ctrl+c,quit,logoff sql transaction, it is auto commit instead of rollback.a

10:43:24 SYSTEM@ usgumsd>select * from v$version;

BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Release 11.1.0.7.0 - 64bit Production
PL/SQL Release 11.1.0.7.0 - Production
CORE    11.1.0.7.0      Production
TNS for IBM/AIX RISC System/6000: Version 11.1.0.7.0 - Production
NLSRTL Version 11.1.0.7.0 - Production

10:43:47 SYSTEM@ usgumsd>

10:40:48 SYSTEM@ usgumsd>show autocommit
autocommit OFF

I notice when you exit sql transaction window by exit, ctrl+c, quit, logoff, the sql transaction will auto commit instead of auto rollback

but if you force close the sql transaction window by alt+f4, clice "X" or kill by task manager , the sql transaction will auto rollback ,

who can help explain it?  and  is it possible set auto rollback even if exit sql transaction window by exit, ctrl+c, quit, logoff.