0.9b (c) 1995 Peter Childs
To avoid mysterious errors you should always use some special chars as first chars of a tail (for example two underscores __) and never use these chars for normal variables (or vice versa).
Another nice method to avoid errors: Always use a number (0..9) for the first character of the tails. This method works because variable names can't begin with a number.
Source: I found this hint in the documentation for the DLL RXU
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