Re: What's the meaning of "Algn" in "objdump -h"?

["Zuxy Meng" <zuxy dot meng at gmail dot com>]

Hi Danny,

2008/6/25 Danny Smith <dansmister@gmail.com>:
> On Wed, Jun 25, 2008 at 3:33 PM, Zuxy Meng <zuxy.meng@gmail.com> wrote:
>> Hi,
>>
>> Under MinGW32 I got the following results:
>>
>> C:\MSYS\home\jimeng>type x.c
>> short b __attribute__((aligned(16)));
>>
>>
>> C:\MSYS\home\jimeng>objdump -h x.o
>>
>> x.o:     file format pe-i386
>>
>> Sections:
>> Idx Name          Size      VMA       LMA       File off  Algn
>>  0 .text         00000000  00000000  00000000  00000000  2**2
>>                 ALLOC, LOAD, READONLY, CODE
>>  1 .data         00000000  00000000  00000000  00000000  2**2
>>                 ALLOC, LOAD, DATA
>>  2 .bss          00000000  00000000  00000000  00000000  2**2
>>                 ALLOC
>>
>> Shouldn't .data be aligned to "2**4" or the "Algn" of an object doesn't mean
>> too much?
>
>
> PE-COFF doesn't support aligned common

Does it mean that uninitialized vars in such objects may get
misaligned when linked together? Or the "aligned" attribute takes
effect only with -fno-common under mingw32?

>
> Compile with -fno-common and you should see .bss aligned correctly
>
> Sections:
> Idx Name          Size      VMA       LMA       File off  Algn
>  0 .text         00000000  00000000  00000000  00000000  2**2
>                  ALLOC, LOAD, READONLY, CODE
>  1 .data         00000000  00000000  00000000  00000000  2**2
>                  ALLOC, LOAD, DATA
>  2 .bss          00000010  00000000  00000000  00000000  2**4
>                  ALLOC
>

-- 
Zuxy
Beauty is truth,
While truth is beauty.
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