[fpc-pascal]Constructor failing...

[Anton Tichawa]

On Thursday 20 March 2003 09:27, you wrote:
> >> > Hi again -
> >> >
> >> > another question; what is the best way to "fail" a constructor call?
> >>
> >> For
> >>
> >> > example, I have a constructor "timage.loadimage()", and I want it to
> >> > return
> >> > "nil" if it encounters a problem (e.g. the file name doesn't exist).
> >>
> >> My
> >>
> >> Use fail :-)
> >
> > But, when I use fail in my simple example program, it returns NIL okay
> > but the Heaptrace function tells me I have two unfreed memory blocks (36
> > bytes).
> > I can't see a memory leak anywhere else in that program, what could cause
> > this? (Heaptrace output is as follows: I am using FPC 1.0.6 btw)
> >
> > Heap dump by heaptrc unit
> > 13 memory blocks allocated : 224/248
> > 11 memory blocks freed     : 188/208
> > 2 unfreed memory blocks : 36
> > True heap size : 20000000 (64 used in System startup)
> > True free heap : 19999792
> > Should be : 19999800
> > Call trace for block 0x0040AEA4 size 24
> >   0x004051AF
> >   0x00401ECC  MYTESTCLASS__CREATE,  line 13 of
> > e:/projects/tests/classtst.pp
> >   0x00401DC6  main,  line 26 of e:/projects/tests/classtst.pp
> >   0x00401059
> > Call trace for block 0x0040AEF4 size 12
> >   0x00405176
> >   0x00401ECC  MYTESTCLASS__CREATE,  line 13 of
> > e:/projects/tests/classtst.pp
> >   0x00401DC6  main,  line 26 of e:/projects/tests/classtst.pp
> >   0x00401059
>
> That is the exception frame that is left on the heap. I don't have the
> time to analyze what the cause is that the exception frame is not removed.
>
>
>
> _______________________________________________
> fpc-pascal maillist  -  fpc-pascal at lists.freepascal.org
> http://lists.freepascal.org/mailman/listinfo/fpc-pascal

Maybe off-topic, but I thought about a constant static object at address 0 or 
so, in order to have the program stilll working when a constructor returns 
NIL (which has value 0). Would that be possible, e. g. under GNU-Linux?

anton tichawa.

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"Adas Methode war, wie sich zeigen wird, Tagträume in offenbar korrekte 
Berechnungen einzuweben."

Doris Langley Moore: Ada, Countess of Lovelace (London 1977).

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Anton Tichawa
Volkertstrasse 19 / 20
A-1020 Wien
mobil: +43 664 52 07 907
email: anton.tichawa at chello.at

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