Program Called or executed directly.

Hi Guys,

I have developed program A and I am calling the program A in another program B.

Now I have to code in program A for two different behavior for the below two scenarios

1. When called by the program B or other programs

2. When it is directly executed. - via selection screen

Is there any System variables (I have checked all but none is suitable) or any other way.

Regards,

Prabhu