A C long is guaranteed to be at least 32 bits in size. long long is guaranteed to be 64 bits.
int depends on the platform. Phil On Thu, Apr 19, 2018 at 10:30 AM, Andres Valloud < avall...@smalltalk.comcastbiz.net> wrote: > The relevant spec does not state 'long' is of any particular size. > > On 4/19/18 1:24 , Serge Stinckwich wrote: > >> >> >> On Thu, Apr 19, 2018 at 9:13 AM, Serge Stinckwich >> <serge.stinckw...@gmail.com <mailto: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/ >> > > >
