That sounds reasonable. your last comment interests me.. we have been getting eOutofmemory errors in logging very frequently on a machine that always has 4GB free ram :D
I'll have to research that more. On Tue, Feb 16, 2010 at 3:06 PM, Jolyon Smith <jsm...@deltics.co.nz> wrote: > Win API returns -1 to indicate “an error”. *Any* error. Not a specific > error. Certainly not specifically a list index error. > > > > Unfortunately, the Win API return value is ALSO the “Item data” value. So > if you store -1 and get -1 back it *could* be an error or it *could* be > the valid result. > > > > The VCL *assumes* that if it gets -1 back then it must be an error. It > then makes matters worse by further *assuming* that it must be a list > index error. > > > > What it *should* do is check the list index provided **itself** BEFORE > sending that index to the WinAPI and then simply give the caller back > whatever value the WinAPI yields (or at least raise LastOSError, not some > assumed exception class). This is a case of the VCL trying to be too > helpful and making a botched job of it in the process. > > > > And as I pointed out, it is now (as of Delphi 2006 at least) fixed (poorly, > imho, but still effectively fixed) in comboboxstrings, just not > listboxstrings. > > > > > > It is similar to the error handling in *TWinControl.GetDeviceContext()*that > naively assumes that a > *GetDCEx()* result of 0 (zero) must indicate an *EOutOfResources*condition. > That bit of “intern code” cost me many lost hours trying to > track down a resource leak when the true problem was actually an invalid > window handle !!!** > > > > > > *From:* delphi-boun...@delphi.org.nz [mailto:delphi-boun...@delphi.org.nz] > *On Behalf Of *Kyley Harris > *Sent:* Tuesday, 16 February 2010 2:51 p.m. > > *To:* NZ Borland Developers Group - Delphi List > *Subject:* Re: [DUG] Is it a bug in latest version of Delphi? > > > > interesting > > > > > if Longint(Result) = LB_ERR then Error(SListIndexError, Index); > > > > it would seem that the error is not in delphi at all. Well.. they are > simply raising the Windows error which say that -1 is the error result for a > bad index access from windows. if delphi were to ignore this error and you > asked for the value at index[99] which was out of bounds and you got -1 > instead of an error I think there would be the same number of complaints > from the other side. > > > > Clearly its the windows API that considers -1 invalid.. not delphi. > > On Tue, Feb 16, 2010 at 2:24 PM, Karl Reynolds < > kreyno...@chocfishsoft.co.nz> wrote: > > On Tue, Feb 16, 2010 at 1:55 PM, Alister Christie > <alis...@salespartner.co.nz> wrote: > > 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. > > Only if you stipulate that you have to remain ignorant of the function > internals. The TObject is converted back and forth from a LongInt in > order to store it anyway (see GetObject and PutObject). > > > > The fact that -1 doesn't work > > is therefor not a bug (unless you can have 1 byte sized objects). > > var x: longint; > > x := -1; // Four bytes > > (May the source be with you). > > Cheer, > Karl > > _______________________________________________ > NZ Borland Developers Group - Delphi mailing list > Post: delphi@delphi.org.nz > Admin: http://delphi.org.nz/mailman/listinfo/delphi > Unsubscribe: send an email to delphi-requ...@delphi.org.nz with Subject: > unsubscribe > > > > > -- > Kyley Harris > Harris Software > +64-21-671-821 > > _______________________________________________ > NZ Borland Developers Group - Delphi mailing list > Post: delphi@delphi.org.nz > Admin: http://delphi.org.nz/mailman/listinfo/delphi > Unsubscribe: send an email to delphi-requ...@delphi.org.nz with Subject: > unsubscribe > -- Kyley Harris Harris Software +64-21-671-821
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