[AccessD] VBA Function with parameters

[Stuart McLachlan]

Not just in the VBA world. :)

You find  then in C, Java, Javascript,  many BASIC dialects for example.
( but they didn't make it into PHP until v8.1)

I use them all the time to create meaningful equates


Boolean "bitwise" comparisons and bitwise manipulation are very useful tools to a 
programmer.

"I am posting this thinking it might be helpful for someone else wondering
what is behind the "addition" of enum parameters set up as powers of two.
"

Please - don't think of "AND" as addition. In fact "OR" is closer to addition.

"AND" is true if, and only if the same bit is set in both values so

If cm And 4  is true if the "4 bit" is set.
That is why we use values that have a single bit set in binary

1 = 0001
2 = 0010
4 = 0100
8 = 1000
(16 = 0001 0000, 32 = 0010 0000 ...)

If cm = 7 (0111) then
cm AND 1 is true
cm AND 2 is true
cm AND 4 is true

If cm = 6 ("0101) then
cm AND 1 is true
cm AND 2 is false
cm as 4 is true



On 8 Nov 2021 at 8:05, Borge Hansen wrote:

> Thanks Paul and Stewart,
> Enum is great...
> Stewart´s example got me googling ...
> 
> Link here explains what Enum is in the VBA world:
>  ...
> So what is behind an expression like this?
> If cm And x ??
>   Bitwise enumeration ...
>