What is a value called, that signals that nothing has happened?

Question

I'm at a loss for what to call that or even what to search for.

What I'm looking for is something like this:

value = None

if something_is_true:
    value = 123

if value is not None:
    send(value)

What is the use of None called in this instance? In my head it sounds something like Cardinal Value, although that is not it.

I'd say "sentinel" or "guard", or even "canary", depending on what its semantic role is. — Federico klez Culloca, Jun 24 '19 at 09:18

score 1 · Accepted Answer · answered Jun 24 '19 at 09:21

1

The word you're probably looking for is "sentinel", that is a variable that triggers some behavior depending on whether it's set or not.

For further information see Sentinel value on Wikipedia.

answered Jun 24 '19 at 09:21

1 Answers1