NAME
	zero_type - return the type of zero

SYNTAX
	int zero_type(mixed a);

DESCRIPTION
	There are many types of zeros out there, or at least there are two.
	One is returned by normal functions, and one returned by mapping
	lookups and find_call_out() when what you looked for wasn't there.
	The only way to separate these two kinds of zeros is zero_type.
	When doing a find_call_out or mapping lookup, zero_type on this value
	will return 1 if there was no such thing present in the mappping, or
	no such call_out could be found. If the argument to zero type is a
	destructed object or a function in a destructed object, 2 will be
	returned. Otherwize zero_type will return zero.

	If the argument is not an int, zero will be returned.

KEYWORDS
	int, mapping

SEE ALSO
	find_call_out
