Structure alignment under AIX 4.3.1

[Jacques_Goussard at cimmetry dot com]

Hi
Found that various structure declaration that are equivalent on other
platforms than AIX4.3.1 (tested Solaris and HPUX) could be not equivalent under
AIX.
Could this alignment pb be a bug :
gcc -v : gcc version egcs-2.91.66 19990314 (egcs-1.1.2 release)
uname -a : AIX neptune 3 4 004558184C00

TEST : compiled with no specific options

#include <stdio.h>
#include <stdlib.h>

typedef struct _D3d {
     double x,y,z;
} D3d;
typedef struct _D3d_tab{
     double x[3];
} D3d_tab;
typedef struct _L1D3_tab {
     long int l;
     double d[3];
} L1D3_tab;
typedef struct _L1D3_struc1{
     long int l;
     D3d d;
} L1D3_struc1;
typedef struct _L1D3_struc2{
     long int l;
     D3d_tab d;
} L1D3_struc2;

 int main()
{
     printf("%i\n",sizeof(L1D3_tab));
     printf("%i\n",sizeof(L1D3_struc1));
     printf("%i\n",sizeof(L1D3_struc2));

     return 0;
}
produces
28
32
28
as output ?
Could it be 4-bytes aligned in first struct, 8-bytes in second and again 4 in
third ???

     Jacques-Olivier Goussard