Re: Different executables of the same source
Brian Ford wrote: gcc doesn't create .o or .exe files. as/ld do respectively :). Of course. There *are* gcc ports that don't use binutils, I know - I've done gcc ports. But most "regular folks" think of "gcc" as a monolithic compiler suite. Anyway, I'll probably report this on the binutils list if I find the time. It's purely cosmetic.. -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Re: Different executables of the same source
On Wed, 11 Feb 2004, Shankar Unni wrote: > Alex Vinokur wrote: > > > How can one get the creation time of object file foo.o? > > > Use "objdump -p". > > But it looks like gcc doesn't stuff a timestamp into the .o, but does > into the .exe. > Just a simple correction. gcc doesn't create .o or .exe files. as/ld do respectively :). So, this would be an as "buglet", I guess. Feel free to follow up in the binutils mailing list if you feel the urge. -- Brian Ford Senior Realtime Software Engineer VITAL - Visual Simulation Systems FlightSafety International Phone: 314-551-8460 Fax: 314-551-8444 -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Re: Different executables of the same source
Alex Vinokur wrote: How can one get the creation time of object file foo.o? Use "objdump -p". But it looks like gcc doesn't stuff a timestamp into the .o, but does into the .exe. Visual C++ puts a timestamp in both the .obj and .exe. -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Re: Different executables of the same source
Alex Vinokur wrote: > How to compute the MD5-sums of executables? "man md5sum" Brian -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Re: Different executables of the same source
"Demmer, Thomas" wrote in message news:[EMAIL PROTECTED] [snip] > Due to this "feature" the MD5-sums > of executables compiled on two different machines will hardly ever > concide. [snip] How to compute the MD5-sums of executables? -- Alex Vinokur mailto:[EMAIL PROTECTED] http://mathforum.org/library/view/10978.html -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Re: Different executables of the same source
"Shankar Unni" wrote in message news:[EMAIL PROTECTED] > Demmer, Thomas wrote: > > > Because the PE header has a field that contains > > the creation time. Due to this "feature" the MD5-sums > > of executables compiled on two different machines will hardly ever > > concide. I have no clue why this feature exists. > > Almost *all* object file formats (ELF, COFF/PE, ...) have such headers, > to tell you when and where it was built. > > How can one get the creation time of object file foo.o? -- Alex Vinokur mailto:[EMAIL PROTECTED] http://mathforum.org/library/view/10978.html -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Re: Different executables of the same source
Demmer, Thomas wrote: Because the PE header has a field that contains the creation time. Due to this "feature" the MD5-sums of executables compiled on two different machines will hardly ever concide. I have no clue why this feature exists. Almost *all* object file formats (ELF, COFF/PE, ...) have such headers, to tell you when and where it was built. -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Re: Different executables of the same source
On Tue, 10 Feb 2004, Alex Vinokur wrote: > "Demmer, Thomas" wrote in message > Please, no plain text email addresses in replies. They are food for spammers. Thanks. > >"Alex Vinokur" wrote: > >>[...] > >>$ gcc foo.c -o x1.exe > >> > >>$ gcc foo.c -o x2.exe > >> > >>$ cmp x1.exe x2.exe > >>x1.exe x2.exe differ: char 137, line 2 > >> > >>Why are x1.exe and x2.exe different? > >> > >Because the PE header has a field that contains > >the creation time. > > > What does 'the PE header' mean? > The section header defined by Microsoft's "Portable Executable" extension to the COFF (Common Object File Format) specification. -- Brian Ford Senior Realtime Software Engineer VITAL - Visual Simulation Systems FlightSafety International Phone: 314-551-8460 Fax: 314-551-8444 -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Re: Different executables of the same source
"Demmer, Thomas" <[EMAIL PROTECTED]> wrote in message > news:[EMAIL PROTECTED] >"Alex Vinokur" wrote: >[...] >>$ gcc foo.c -o x1.exe >> >>$ gcc foo.c -o x2.exe >> >>$ cmp x1.exe x2.exe >>x1.exe x2.exe differ: char 137, line 2 >> >>Why are x1.exe and x2.exe different? >Because the PE header has a field that contains >the creation time. [snip] What does 'the PE header' mean? -- Alex Vinokur mailto:[EMAIL PROTECTED] http://mathforum.org/library/view/10978.html -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Re: Different executables of the same source
"Alex Vinokur" wrote: [...] >$ gcc foo.c -o x1.exe > >$ gcc foo.c -o x2.exe > >$ cmp x1.exe x2.exe >x1.exe x2.exe differ: char 137, line 2 > >Why are x1.exe and x2.exe different? Because the PE header has a field that contains the creation time. Due to this "feature" the MD5-sums of executables compiled on two different machines will hardly ever concide. I have no clue why this feature exists. Ciao Tom Best regards / Mit freundlichen Grüssen, Thomas Demmer Kraft Foods R&D Inc. Chocolate WW Process Development Tel.: +49 (0)89 62738-6302 Fax: +49 (0)89 62738-86302 Thought of the day By doing just a little every day, you can gradually let the task completely overwhelm you. -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
Different executables of the same source
$ uname -sr
CYGWIN_NT-5.0 1.5.5(0.94/3/2)
$ gcc --version
gcc (GCC) 3.3.1 (cygming special)
[snip]
$ cmp -v
cmp (GNU diffutils) 2.8.4
[snip]
--- C program (foo.c) ---
int main()
{
return 0;
}
-
$ gcc foo.c -o x1.exe
$ gcc foo.c -o x2.exe
$ cmp x1.exe x2.exe
x1.exe x2.exe differ: char 137, line 2
Why are x1.exe and x2.exe different?
--
Alex Vinokur
mailto:[EMAIL PROTECTED]
http://mathforum.org/library/view/10978.html
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