__attribute__ ((aligned(8))) doesn't work with typedefs
I'm currently using the February 2007 version of Sun Studio Express in order to get support for __attribute__ ((aligned(8))).
While trying to create a long long type that would be aligned to an 8 bytes boundary on x86 instead of the usual 4 bytes, I discovered that the __attribute__ ((aligned(8))) directive only works on variables, not on typedefs...
if I use:
long long __attribute__((aligned (8))) foo;
then foo is 8 bytes aligned as expected.
If I use:
typedef __attribute__ ((aligned (8))) long long bar;
bar foo;
then foo is 4 bytes aligned instead of the expected 8.
This behavior is not present in gcc where foo will get an 8 bytes alignment in both cases. Is there any way to fix this or to make it works?
# 2
Here's a sample program that reproduce the problem here.
spotvin@tl-sol10i64-01 % cat testalign.c
[code]
#include <stdio.h>
typedef __attribute__ ((aligned(8))) long long aligned_longlong_t;
struct typedef_longlong {
unsigned intdummy;
aligned_longlong_tlonglong;
};
struct manual_longlong {
unsigned intdummy;
long long __attribute__ ((aligned(8))) longlong;
};
int
main (void)
{
printf("sizeof(struct typedef_longlong) = %d\n", sizeof(struct typedef_longlong));
printf("sizeof(struct manual_longlong) = %d\n", sizeof(struct manual_longlong));
return 0;
}
[/code]
spotvin@tl-sol10i64-01 % suncc -V
cc: Sun C 5.9 SunOS_i386 Build40_1 2007/02/08
usage: cc [ options] files. Use 'cc -flags' for details
spotvin@tl-sol10i64-01 % suncc -o testalign testalign.c
spotvin@tl-sol10i64-01 % ./testalign
sizeof(struct typedef_longlong) = 12
sizeof(struct manual_longlong) = 16
# 3
Yeah, there were problems with typedef'ing aligned attribute and then doing derived types from it.Right now this problem is being worked on.There is a good chance for the fix to get its way into release. You can cross fingers for it ;)regards,__Fedor.
SFVa at 2007-7-10 3:18:22 >
# 5
Just to let you know - this problem is fixed in Sun Studio 12 release:
] suncc -o testalign testalign.c -V
cc: Sun C 5.9 SunOS_i386 2007/05/03
acomp: Sun C 5.9 SunOS_i386 2007/05/03
ld: Software Generation Utilities - Solaris Link Editors: 5.11-1.553
] ./testalign
sizeof(struct typedef_longlong) = 16
sizeof(struct manual_longlong) = 16
]
regards,
__Fedor.
SFVa at 2007-7-10 3:18:22 >
