Re: [Pharo-users] [UFFI] Using a nested structure

July 5, 2016

      Hi Merwan,

I tested this on Pharo 6 and it is working in Windows. However, in 32 bits
Window doubles have an 8 byte alignment, unlike Linux where they have a 4
byte alignment.

Can you try doing the following before performing the ffi call in Windows,
if you are moving an image from Linux or OS X:

Vec3 rebuildFieldAccessors.
Position rebuildFieldAccessors.

Best regards,
Ronie

2016-07-05 11:11 GMT+02:00 Merwan Ouddane <merwanouddane@gmail.com>:
...
Hi,
I have an issue whith nested structures.
I made some "dummy" structures in c:
typedef struct vec3 {
     double data[3];
} vec3;
typedef struct position {
     int i;
     vec3 vec;
} position;
And a "dummy" function to fill it:
void fillStruct(position *position)
{
    position -> i = 19;
    (position -> vec).data[0] = 1;
    (position -> vec).data[1] = 2;
    (position -> vec).data[2] = 3;
}
But I can't make the nested structure work.
The "i" is correctly set to 19 but I have values that doesn't make any
sense in the vec3 structure.
In Pharo
I declared the Double3 type for the array inside Vec3:
Double3 := FFITypeArray ofType: 'double' size: 3
Vec3>>fieldsDesc
    ^ #(
    Double3 v;
)
And the position:
Position>>fieldsDesc
    ^ #(
    int i;
    Vec3 vec;
)
The ffi call:
^ self ffiCall: #(void fillStruct(Position *position)) module: 'Test.dll'
Sorry for the long / messy mail :p
Any clues ?
Cheers,
Merwan

Re: [Pharo-users] [UFFI] Using a nested structure

Ronie Salgado