.\"determine whether or not a given variable is undefined.
.TH undefinedp 3

.SH NAME
undefinedp() - determine whether or not a given variable is undefined.

.SH SYNOPSIS
int undefinedp(mixed arg);

.SH DESCRIPTION
Return 1 if `arg' is undefined.  'arg' will be undefined in the following
cases:
.TP
1.
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, "???")).
.TP
2.
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]).

.SH SEE ALSO
nullp(3), mapp(3), stringp(3), pointerp(3), objectp(3), intp(3).