On Thu, Apr 19, 2018 at 9:13 AM, Serge Stinckwich < serge.stinckw...@gmail.com> wrote:
> I try to understand differences between 32 bits and 64 bits FFI support > for C structures. > > I build a class called MyStruct subclass of FFIExternalStructure. > and define a layout for this structure like this one : > > MyStruct class>>fieldsDesc > "self rebuildFieldAccessors" > > ^ #( > int index ;) > > and then I generate automatically the field accessors. > > If I use a 32 bit VM, the following method is generated to access the > index field : > > index > "This method was automatically generated" > ^handle signedLongAt: OFFSET_INDEX > > and if I use a 64 bits VM, the same method is generated ... > > I'm a bit puzzled because, if sizeof(int) = sizeof(long) in a 32 bits VM, > they have different for 64 bits VM (sizeof(int) = 4 and sizeof(long) = 8). > > Someone to explain me or this is a bug ? > > Ok I have understood ... signedLongAt: method does not return a long as the name seems to indicate but in fact a 32 bits integer. So it works in both 32 and 64 bits VM. Maybe signedInt32At: would have been a better name :-) -- Serge Stinckwich UMI UMMISCO 209 (SU/IRD/UY1) "Programs must be written for people to read, and only incidentally for machines to execute."http://www.doesnotunderstand.org/
