On 06/12/2012 13:16, Jonas Maebe wrote:
On 06 Dec 2012, at 14:03, Martin wrote:
Yet what I do not understand, is why I get that message as warning
(as opposed to a hint). If I understand it right (I have not tested,
maybe it gives a warning on 64 bit target too, if so ignore the
rest), and I compile for a 64bit target, then it downgrades to a
hint again?
Yes. If you typecast an integer to a pointer and both have the same
size, you get a hint. If they have a different size, you get a warning.
The only difference is, that in the above example, if compiled for a
32 bit system, I already may have broken code. But then what it
actually means is that I should get warning about a truncating the
value.
b := byte(a);
Gives no warning at all.
That's because truncating integers cannot result in invalid addresses.
The warning was added to help people moving from 32 bit to 64 bit
systems and using longint typecasts in their programs to convert
between addresses and integers. There are very few cases whereby
discarding the upper 32 bit of a pointer is intended or results in
valid code.
Ok, thanks.
It was only that I was working on 3cd party code, with many pointer
casts. And some did warn, some not (add to that that the IDE did hide
the hints. And I couldn't work out why I only got some warnings, and not
others.
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