[fpc-devel]PowerPC, TypInfo

Jonas Maebe jonas at zeus.ugent.be
Sat Aug 14 23:59:55 CEST 2004

On 14 aug 2004, at 21:07, Mattias Gaertner wrote:

>> The GetOrdProp is used to read boolean values. It reads a longint and
>> applies "and $ff" to get only the lowest byte. Under PowerPC the 
>> boolean
>> value is stored just like under i386 in the first byte. Reading the
>> longint under i386 works, but of course it does not under powerpc.
>> So, either the compiler is wrong or the GetOrdValue function is wrong.
>> Which one should I report?
> I just found out, that this is also the case for ShortInt, SmallInt, 
> Word
> and Byte, but not for enums.

To me, the fact that it always reads a longint regardless of the size 
of the property seems to be inherently wrong. What if the last field of 
a class is a byte? Then you can read past the end of the class, 
possibly into unallocated memory causing a crash, no?


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