safety: null checks

[Patrick Schluter]

On Monday, 23 November 2020 at 12:39:05 UTC, Ola Fosheim Grøstad 
wrote:
> On Monday, 23 November 2020 at 12:28:39 UTC, Patrick Schluter 
> wrote:
>> No. null is not a trap representation as a C standard would 
>> call it. It is a valid value for a pointer. Dereferencing it 
>> is an entirely other thing.
>
> A trap is an interrupt at the hardware level. It has nothing to 
> do with C.

Read the C standard, they explain what a trap representation is. 
It has nothing to do with an interrupt. I refer to the C standard 
because they make the difference between allowed pointer values 
and unallowed values even if never dereferenced.

Read the selected answer on this stackoverflow [1] page, he 
explains it better than me.

[1]: 
https://stackoverflow.com/questions/6725809/trap-representation