Thank you for a clear explanation!
Cheers,
Michael Switzer
Jump Productions
Phone +64 7 838 3371
Fax +64 7 838 3372
Email [EMAIL PROTECTED]
-----Original Message-----
From: Carl Reynolds <[EMAIL PROTECTED]>
To: Multiple recipients of list delphi <[EMAIL PROTECTED]>
Date: 28 July, 1999 9:15 AM
Subject: RE: [DUG]: Any comments
>Think of a TBitmap as a pointer to a block of memory.
>
>function myapp.getaBM(oldBM:tbitmap):tbitmap;
>var bitmap:tbitmap
>begin
>
> // oldBM->memblock1, Bitmap->nil, Result->nil
>
>bitmap:=tbitmap.create;
>
> // oldBM->memblock1, Bitmap->memblock2, Result->nil
>
>//rest bitmap initialize here
>bitmap:=oldBM;
>
> // oldBM->memblock1, Bitmap->memblock1, Result->nil, no pointers
>to memblock2 so memblock2 is lost!
>
>result:=bitmap;
>
> // oldBM->memblock1, Bitmap->memblock1, Result->memblock1
>
>bitmap.free; //gwan get lost result
>
> // oldBM->[freed], Bitmap->[freed], Result->[freed]
>
>end;
>
>So the bitmap that you passed to this function has been freed by it, and
>the function will return this (already freed) bitmap. Access violation
>city. And the function leaks memory to boot (a TBitmap is created and
>promptly forgotten about)...
>
>Cheers,
>
>Carl Reynolds Ph: +64-9-4154790
>CJN Technologies Ltd. Fax: +64-9-4154791
>[EMAIL PROTECTED] DDI: +64-9-4154795
>PO Box 302-278, North Harbour, Auckland, New Zealand
>12 Piermark Drive, North Harbour Estate, Auckland, NZ
>Visit our website at http://www.cjntech.co.nz/
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