Help understanding piece of code with Millis

Using Arduino Programming Questions
1

Please help me understand what does this piece of code does:

	unsigned long nowtime = millis();
	unsigned long update = 0;
	if (nowtime > update)
	{
		pagenumber();
		update += 10000;
	}

It lies in void loop part.
I understand it repeaditely calls pagenumber(), but how often? This update tries to catch nowtime? Why 10000?!

2

Every ten seconds, pagenumber is called, assuming the variables have global scope.

3

That code, as presented, will ALWAYS call pagenumber(), on EVERY iteration of loop(), because when the if is evaluated, nowtime will ALWAYS be > update!

And, even if update is global or static, it will NOT do the delay properly when update gets to within 10000 of its maximum value of 2^31.

If you want it to do otherwise, update needs to be either global or static, so it does NOT get zeroed on every iteration of loop().

Regards,
Ray L.

4