Benoit,

Your English is great.

It violates encapsulation to pass an object property out to some other things by reference.

To get an array property out you have to acopy() it too/from a local array.

acopy( this.aStuff, laStuff )
=TheUDF( @laStuff )
acopy( laStuff, this.aStuff )

You might want to reevaluate the architecture that is requiring this kind of manipulation. If you are translating old Clipper code it would be a good time to redesign to make it more object-oriented.

>I know how to define a array property but how can i passe by reference this array to a function outside the form. my function is in a .prg This prg hold some function use from other form.