.\"determine whether or not a given variable is undefined.
.DT
undefinedp
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undefinedp

.SH Name
.SI 5
undefinedp() - determine whether or not a given variable is undefined
.EI

.SH Synopsis
.SI 5
int undefinedp( mixed arg );
.EI

.SH Description
.SP 5 5
Return 1 if `arg' is undefined.  `arg' will be undefined in the following
cases:
.EP

.SO 5 2 70
	*	it is a variable set equal to the return value of a call_other to a non-existent method (e.g. arg = call_other(obj, "???")).
	*	it is a variable set equal to the return value of an access of an element in a mapping that doesn't exist (e.g. arg = map[not_there]).
	*	it has not yet been initialized.
	*	it points to a destructed object.
	*	it is a function (formal) parameter that corresponds to a missing actual argument.
.EO

.SH See also
.SI 5
stringp(), pointerp(), objectp(), intp(), bufferp(), floatp(),
functionp(), errorp(), mappingp(), typeof()
.EI
