# Package =TWiki::AccessControlException **extends** `Error` Exception used raise an access control violation.
## [[ClassMethod]] **new** `($mode,$user,$web,$topic,$reason)` - `$mode` - mode of access (view, change etc) - `$user` - user object doing the accessing - `$web` - web being accessed - `$topic` - topic being accessed - `$reason` - string reason for failure All the above fields are accessible from the object in a catch clause in the usual way e.g. `$e->{web}` and `$e->{reason}` ## [[ObjectMethod]] **stringify** `() -> $string` Generate a summary string