isEmail function

[Brett]

Quick question, I have this isEmail function below.  Should this cover
the basis for verifying an email address or am i missing an possibility?


# input : scalar
# output: true or false
sub isemail {
    my($val) = shift(@_);
    return 0 if (!defined($val));
    return $val =~ /
                      ^\w+(?:[\.-]?\w+)*@\w+(?:[\.-]?\w+)*(?:\.[a-zA-Z]{2,3}){1}$
                      |
                      ^\w+(?:[\.-]?\w+)*@(?:\d{1,3}\.){3}(?:\d{1,3}){1}$
                   /x ? 1 : 0;
}