Try with this:

cat > test_align.c <<END
#include <stdio.h>

struct foo1 {int a; long long b; int d;};
struct foo2 {int a; double c; int d;};

int main() {
struct foo1 x;
struct foo2 y;
printf("size of x = %d\n",sizeof(x));
printf("size of y = %d\n",sizeof(y));
return 0;
}
END
i686-w64-mingw32-gcc test_align.c
 ./a.exe

size of x = 24
size of y = 24

so at leat in windows (mingw) the alignment is 8 bytes for both long long
and double.
I have no 32bits linux handy, but it should be easy enough to pass the same
test...

Le ven. 29 mai 2020 à 16:45, Nicolas Cellier <
nicolas.cellier.aka.nice at gmail.com> a écrit :

> Good catch!
> Wikipedia page does not even agree on longlong... But it's not the
> ultimate normative reference, better check by ourselves!
> https://en.wikipedia.org/wiki/Data_structure_alignment
>
> Le ven. 29 mai 2020 à 15:53, Marcel Taeumel <marcel.taeumel at hpi.de> a
> écrit :
>
>> Hi, there.
>>
>> In ExternalType class >> #initializeAtomicTypes, there is an interesting
>> claim and a piece of dead code:
>>
>> "On 32 bits Windows and MacOS, double and long have an alignment of 8.
>> But on Linux, their alignment is 4"
>> (Smalltalk wordSize = 4 and: [Smalltalk platformName = 'unix']) ifTrue: [
>> (#('double longlong ulonglong') includes: typeName) ifTrue: [
>> byteAlignment := 4
>> ]
>> ].
>>
>> As you can see, there are single quotes missing and so will the path
>> "byteAlignment  := 4" never be reached.
>>
>> I tried to figure out whether one should either fix the conditional or
>> remove the entire passage. Maybe this got long fixed inside the FFI plugin?
>>
>> Best,
>> Marcel
>>
>>
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