Same code build twice => diff binary

[Viviana Vc]

Hi all,

I am using Win2k, VS. NET 7.1 (MS development Environment 2003 7.1.3088)
and I noticed that by building the exact same code twice the generated
binaries are different (not much, but they are). To be sure I tried a
simple console application like void main(){} and 2 times rebuilding the
project gets 2 different binaries.

Has anybody any clue why this happens?
Could I somehow change a setting or something to remove those diff (I
mean from the same code to get identical binaries)?

Thanks in advance,
Viv

[Allan Bruce]

Re: Same code build twice => diff binary


"Viviana Vc" <vcotirlea@hotm ail.com> wrote in message
news:2idu3bFlvg crU1@uni-berlin.de...[color=blue]
> Hi all,
>
> I am using Win2k, VS. NET 7.1 (MS development Environment 2003 7.1.3088)
> and I noticed that by building the exact same code twice the generated
> binaries are different (not much, but they are). To be sure I tried a
> simple console application like void main(){} and 2 times rebuilding the
> project gets 2 different binaries.
>
> Has anybody any clue why this happens?
> Could I somehow change a setting or something to remove those diff (I
> mean from the same code to get identical binaries)?
>
> Thanks in advance,
> Viv[/color]

void main(){} is undefined bahaviour therefore the compiler is free to do
what it wants. Vey unlikely this is the cause however. I am not sure about
the format of an exe, but could it be the timestamps that are causing them
to be different?
Allan

[Viviana Vc]

Re: Same code build twice =&gt; diff binary

I found the following article:

http://support.microsoft.com/default.aspx?scid=kb;en-us;164151

which tells that indeed the timestamp is the diff, but I couldn't find
in VC++ IDE any setting to disable the timepstamp stuff, and I assume
this should be somehow doable.

Thx,
Viv

On Sat, 05 Jun 2004 14:55:45 +0200, Viviana Vc <vcotirlea@hotm ail.com>
wrote :
[color=blue]
>Hi all,
>
>I am using Win2k, VS. NET 7.1 (MS development Environment 2003 7.1.3088)
>and I noticed that by building the exact same code twice the generated
>binaries are different (not much, but they are). To be sure I tried a
>simple console application like void main(){} and 2 times rebuilding the
>project gets 2 different binaries.
>
>Has anybody any clue why this happens?
>Could I somehow change a setting or something to remove those diff (I
>mean from the same code to get identical binaries)?
>
>Thanks in advance,
>Viv[/color]

[AlexS]

Re: Same code build twice =&gt; diff binary

Hi, Viviana

depending on settings you can get different timestamps and versions in
binaries. Which will cause different hashes and some other fields - don't
remember now exactly wich ones. If you are really interested - check PE
format description for .Net assemblies on MSDN.

HTH
Alex

"Viviana Vc" <vcotirlea@hotm ail.com> wrote in message
news:2idu3bFlvg crU1@uni-berlin.de...[color=blue]
> Hi all,
>
> I am using Win2k, VS. NET 7.1 (MS development Environment 2003 7.1.3088)
> and I noticed that by building the exact same code twice the generated
> binaries are different (not much, but they are). To be sure I tried a
> simple console application like void main(){} and 2 times rebuilding the
> project gets 2 different binaries.
>
> Has anybody any clue why this happens?
> Could I somehow change a setting or something to remove those diff (I
> mean from the same code to get identical binaries)?
>
> Thanks in advance,
> Viv[/color]

[Jochen Kalmbach]

Re: Same code build twice =&gt; diff binary

Viviana Vc wrote:
[color=blue]
> I am using Win2k, VS. NET 7.1 (MS development Environment 2003
> 7.1.3088) and I noticed that by building the exact same code twice the
> generated binaries are different (not much, but they are). To be sure
> I tried a simple console application like void main(){} and 2 times
> rebuilding the project gets 2 different binaries.
>
> Has anybody any clue why this happens?[/color]

At least the time-stamp is different.


[color=blue]
> Could I somehow change a setting or something to remove those diff (I
> mean from the same code to get identical binaries)?[/color]

In general: No. You can change the timestamp "by hand".


For more info see:
Microsoft Portable Executable and Common Object File Format
Specification
http://www.microsoft.com/whdc/system...re/PECOFF.mspx


It was already discussed several times in some newsgroups; see for
example:

http://groups.google.de/groups?&threadm=enwAkowrBHA.600%40tkmsftngp04

--
Greetings
Jochen

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