I am designing an auto SAS program. I want it execute at the very first time I start SAS everyday and it should be executed only once. That is to say, I may start SAS several times this day, but the auto program will be executed only the first time I start SAS.
There are also some restricts: 1. It won't be executed if I have not use my SAS one day; 2. It won't be executed if I happen to working on SAS at daybreak;
This has some subtle sharp edges you might hit in cases where the SAS system is very very busy. A script could be quite prone to race conditions on busy servers. If you have lots of sessions spawning you might miscount if two sessions spawn at almost identical times.
If this is just your workstation you are unlikely to miscount because of races with many SAS sessions starting in the same microsecond.