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Find a flaw in the logic
Message
From
13/01/2006 11:01:44
 
 
To
13/01/2006 10:43:51
Dragan Nedeljkovich
Now officially retired
Zrenjanin, Serbia
General information
Forum:
Visual FoxPro
Category:
Classes - VCX
Environment versions
Visual FoxPro:
VFP 9
OS:
Windows XP SP2
Database:
Visual FoxPro
Miscellaneous
Thread ID:
01086027
Message ID:
01086550
Views:
19
>>>>No risk at all since I'm using lparameters and not passing variable by reference.
>>>
>>>Ah, but, as far as I know, objects are always passed by reference, because the object type variables are references to actual objects. So if you pass an object by value, you do get a new variable, which still refers to the same object.
>>>
>>>If it wasn't so, your changes to the object would be lost as soon as your code exits - but you know your code works.
>>
>>Dragan, I think you're mixing us up here. If SET UDFPARMS is set to VALUE and a variable holding an object reference is sent as a parameter in a normal way, then that variable cannot be changed in the called function/procedure/method. If the setting is REFERENCE, then the variable can be changed. I think your usage of 'passed by reference' obfuscates things here.
>
>This is true for any variable - but what is a content of an object reference variable? The reference to an object. And even if you have a copy of such a variable (i.e. passed by value), it only increases the reference count in the object, it doesn't create a copy of the object. So, substantially, an object passed as a parameter is always passed by reference. Or, more precisely, it's passed as a reference.
>
>You can check this yourself - pass thisform by value to any piece of code which will change its caption and see what happens.

Pass thisform by reference, change its value and see what happens when you use it. See Re: Find a flaw in the logic Thread #1086027 Message #1086509
Groet,
Peter de Valença

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