$ERR

References:

If an operation results in an error, the $ERR data type is returned. Check using the type function: if (@result.type()==$ERR) something;

Under the hood, the $ERR type is a $LIST, and the same commands can be used to get more details on the error.

> (1/0).type()==$ERR
true

Part of $OBJ

iferr(new)

If value is $ERR type, the new is used. Otherwise the value is used.

(10/2).iferr(55) -> 5
(10/0).iferr(55) -> 55