Thanks Hilmar and well explained (as usual). Ever thought of writing a book "Boolean Algebra for Dummies?" (you know, them bright orange ones in the bookshops). I would buy it!

Best



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>>>bitand(nFlags, bitxor(nReset, 0xffffffff))
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>>Albert,
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>>What is the significance of "0xffffffff" ? Sorry to be thick. Could you explain the logic of the above if you have the time?
>
>"ox" is the prefix to indicate that the following number is in hexadecimal (base 16 instead of base 10). Base 16 has 16 digits: 0-9 and A-F (A means 10, B means 11, ... F means 15).
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>HTH, Hilmar.