Re: Subtleties of __attribute__((packed))

From: Jan Blunck
Date: Wed Dec 06 2006 - 11:26:38 EST


On Wed, Dec 06, Phil Endecott wrote:

>
> To see a difference with your example structs you need to compare these two:
>
> struct wibble1 {
> char c;
> struct bar1 b1;
> };
>
> struct wibble2 {
> char c;
> struct bar2 b2;
> };
>
> struct wibble1 w1 = { 1, { 2, {3,4,5} } };
> struct wibble2 w2 = { 1, { 2, {3,4,5} } };
>
> Can you try that with your compilers? I get:
>

As I expected, I get:

.file "packed2a.c"
.globl w1
.data
.align 2
.type w1, @object
.size w1, 14
w1:
.byte 1
.byte 2
.4byte 3
.byte 4
.zero 3
.4byte 5
.globl w2
.align 2
.type w2, @object
.size w2, 14
w2:
.byte 1
.byte 2
.4byte 3
.byte 4
.zero 3
.4byte 5
.ident "GCC: (GNU) 4.1.2 20060531 (prerelease) (SUSE Linux)"
.section .note.GNU-stack,"",@progbits
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/