general / undefinedp

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NAME

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

SYNOPSIS

int undefinedp( mixed arg );

DESCRIPTION

Return 1 if 'arg' is undefined.  'arg' will be undefined in the follow‚Äź
ing cases:

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, "???")).

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]).

SEE ALSO

mapp(3),  stringp(3),  pointerp(3),  objectp(3),  intp(3),  bufferp(3),
floatp(3), functionp(3), nullp(3), errorp(3)