onError property Null safety
A callback that is invoked when an unhandled error occurs in the root isolate.
This callback must return true
if it has handled the error. Otherwise,
it must return false
and a fallback mechanism such as printing to stderr
will be used, as configured by the specific platform embedding via
Settings::unhandled_exception_callback
.
The VM or the process may exit or become unresponsive after calling this callback. The callback will not be called for exceptions that cause the VM or process to terminate or become unresponsive before the callback can be invoked.
This callback is not directly invoked by errors in child isolates of the
root isolate. Programs that create new isolates must listen for errors on
those isolates and forward the errors to the root isolate. An example of
this can be found in the Flutter framework's compute
function.
Implementation
ErrorCallback? get onError => _onError;
Implementation
set onError(ErrorCallback? callback) {
_onError = callback;
_onErrorZone = Zone.current;
}