[DUG] Is it a bug in latest version of Delphi?

[Alister Christie]

I think the point I was trying to make is that it is that the method 
(/array indexer or whatever) was expecting a TObject - passing anything 
else could result in unexpected results.  The fact that -1 doesn't work 
is therefor not a bug (unless you can have 1 byte sized objects).

Alister Christie
Computers for People
Ph: 04 471 1849 Fax: 04 471 1266
http://www.salespartner.co.nz
PO Box 13085
Johnsonville
Wellington 



Jolyon Smith wrote:
>> you should care greatly, because this is violating OOP principles 
>>     
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> I care about code that works and gets a job of work done.  "OO Principles" are for the classroom.
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>> Obviously the GetObject source cares somewhat about what -1 points to.
>>     
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> No, it doesn't.  It simply gets confused because the Windows API uses "-1" to indicate that an error occurred in retrieving an item's data and the VCL is then naively assuming that ANY error in retrieving an item's data must be a List Index error.
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> Even though it could (and should) specifically test for index validity before calling the API and so discount that possible source of an error from the outset.
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> Indeed, the TObject(-1) result is cast BACK to a LongInt(-1) for testing against the simple value LB_ERR (which == -1) ... the source of this error has nothing what-so-ever to do with the casting of the value as TObject.
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