[fpc-devel]PowerPC, TypInfo

[Jonas Maebe]

On 15 aug 2004, at 00:20, Florian Klaempfl wrote:

>> 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?
>
> No. Classes are always allocated on the heap so the memory block is 
> always at least a multiple of 4.

So? What if the last field is a byte and is stored in the last byte of 
the e.g. 100 bytes that the class occupies? Keep in mind that 
getordprop does not necessarily read from a 4-byte aligned address. It 
simply reads 4 bytes from the start address of the field, and then ands 
the result with $ff if the size of the field was 1 byte.


Jonas