What does PURE mean in startup assigns?

[ChaosLord]

Do not ever use PURE unless you know for a fact that the command really is pure.

Using the PURE option on impure commands will lead to disasterous results.

[ChaosLord]

@mel_zoomy

Yes they must be written and/or assembled and/or compiled a certain way.

Since you are coding C... which compiler are you using?

Technically a pure program must place ALL global variables in allocated memory or on the stack.  For example local variables go on the stack in C so they are 100% pure.  But normal variables just go into regular memory and that is impure.  But if you do an AllocMem() and store the vars in that memory then that is pure.

PURE means that the code can be executed multiple times simultaneously.

[ChaosLord]

In C you don't need to AllocMem() any vars or use the stack to create a pure exe.  You just need to compile and link with the proper pure options and the compiler takes care of everything for you.

[ChaosLord]

@lurkist

Just run 1 of those apps twice at the same time and the contents of the entire Amiga universe running on your machine will be displaced in a firey cataclysmic crash.  Well it was nice to have known you. Please write your will and leave all your Amigas to me before you try it.  Thanx.  :-D

[ChaosLord]

@mel

Yes you can use constants any way you want and still be pure.
That is why I said "variables".  You are only limited regarding data which is writeable.