NAME
	zero_type - What kind of a zero is it?

SYNTAX
	int zero_type(mixed arg);

DESCRIPTION
	If you index a mapping and it returns zero, you can use this
	efun to check weather it was a zero in the mapping or if the index
	wasn't present.

	It returns:
		0 if it was a number
		1 undefined, Depending on the value you are testing, 
                  this can mean the following things:
		  o it wasn't present in the mapping (mapping index)
		  o there was no such call_out (find_call_out, remove_call_out)
		2 if it was a destructed object
		3 if it was a function in a destructed object
		-1 if the argument is something other than a number

NOTA BENE
	The values 2 and 3 should only be used for debugging as those
	might be changed in the future.

SEE ALSO
	stringp, pointerp, objectp, mappingp, functionp, floatp, intp