Can a pointer be null and if so can it be tested for?

Ah, just the person who might be able to help me,
Rob, I have just bought some cute little ASC712 current sensing chips, they're 8 legged SMD, so their small ok.
It's been years since I played with PCB programs, I think protel was the program I used to use.
But, I use Linux and OSX these days.

Any advice regarding software or anything.

Paul