From Xojo Documentation
| This class is only available on the macOS platform.
For cross-platform development, use ＃If...＃Endif with the Target... specifiers to make sure you will not attempt to use this class on an incompatible platform.
Generated by an Objective-C exception around Objective-C Declare statements.
If an Objective-C exception is raised due to an Objective-C Declare, it will be converted into a ObjCException object and raised through the normal exception system. ObjCException has a handle property, which allows you to get the underlying exception object (typically an instance of NSException).