>I want to know the array size of a passing array!
>e.g.
>
>Aused(NumUsedTable)
>CallFunc(NumUsedTable)
>
>Define Function CallFunc
>Lparameters AryName
>
>* then?

If you didn't touch the defaults, parameters are passed by value, DO..WITH pass params by reference regardless of "SET UDF ..". When you pass an array to a function, as you did, by value you actually pass the value of first item, not the array itself. To pass the array you should pass it by reference. To do it regardless of "SET UDF.." precede it with an "@" sign.

=Aused(aNumUsedTable)
=CallFunc(aNumUsedTable)

* Callfunc
lparameters aNumTables
? aNumTables    && First tablename
? aNumTables[2] && Produce error - aNumTables is not an array

=Aused(aNumUsedTable)
=CallFunc(@aNumUsedTable)

* Callfunc
lparameters aNumTables
? aNumTables    && First tablename
? aNumTables[2] && Second tablename and so on

Beware when you pass by reference you're actually passing the address of var so if the function changes the value it would be changed upon return.
Cetin