[litwr]

Originally Posted by roondar

Apart from the official and unofficial programming guides for the system of course. The OS change is irrelevant as on later KS roms you're still not supposed to do this. I.E. it works by accident in later versions, not by design.

It is just your assumption without the real proof.

Originally Posted by roondar

Be honest here: have you actually read any of these books?

I was confused by a fact that $ can only be used inside the IF-command. However AmigaDOS Inside & Out (1991) in Engilsh missed $'s completely. Anyway thank you but you can notice that my point had some basis too.

Originally Posted by roondar

Anyway, the example CheckRet actually supports what I said - if the OS doesn't support return codes other than 0,5,10 or 20 then that is a totally superfluous command to have. Also note here that the command FAILAT can accept any return code, including numbers over 20 (the example in the Amiga DOS manual with my A500 actually uses FAILAT 25). The confusion here is that you're mistaking the IF functions built in condition checks with the OS supporting only certain options.

Edit: note here that the long-form Amiga DOS manual (which the short form one you and I have refers to all the time) makes it clear that the IF flags trigger if the return code >= 0,5,10 or 20 and not = 0,5,10 or 20. This means that a program that returns with a return code which is not 0,5,10 or 20 can be detected through IF.

You can't distiguish more than five variants. How to choose one of the six variants? No way before WB 2. So CheckRet is quite useful for such cases.

Originally Posted by idrougge

The return code of the last command is always in the RC variable and can be checked as any variable; or was this not in place in 1.3? Sounds unlikely.

Thank you very much. I corrected my claim "3) no way to use program return codes, only few "standard" return codes are allowed (exactly 0, 5, 10, 20) until WB 2.0"