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 *.o not recongised: file format not recognised 
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Joined: Sat Jul 25, 2009 6:10 am
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Post *.o not recongised: file format not recognised
I seem to get this while compiling my Operating System (when linking kernel_start.o). I think it's the ld software, because it happens with many different examples over the net. Any ideas?

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Michael Sammels

OS Developing is 10% luck, 20% skill, 15% concentrated power of will. 5% pleasure, 50% pain, and a 100% reason continue the game.


Sun Oct 25, 2009 1:35 pm
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Joined: Wed Oct 14, 2009 9:39 am
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Post Re: *.o not recongised: file format not recognised
What is the format you are using? ELF or PE/COFF

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Charles Timko
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Sun Oct 25, 2009 7:07 pm
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Post Re: *.o not recongised: file format not recognised
".o" is not a format, rather a file extension.

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Bogdan


Mon Oct 26, 2009 12:13 am
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Joined: Sat Jul 25, 2009 7:44 am
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Post Re: *.o not recongised: file format not recognised
Bogdan, the *.o file type, is a file format, but it is a format that contains an intermediate object, which is usually linked to form a complete program.

What is the command line you are using to compile the *.o files?
Also, what is the platform you are compiling/linking on?

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Kieran C G Foot


Mon Oct 26, 2009 3:41 am
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Post Re: *.o not recongised: file format not recognised
Nope, it's just an extension. It can be used with any format from a.out to ELF and COFF.

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Bogdan


Mon Oct 26, 2009 4:31 am
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Post Re: *.o not recongised: file format not recognised
Yes, exactly, the .o on the end of the file just denotes the fact that the file contains object data, regardless of its internal format.

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Kieran C G Foot


Mon Oct 26, 2009 5:02 am
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Post Re: *.o not recongised: file format not recognised
Exactly. I wanted to clarify this because if the error spat by the linker is anything like the one in the thread title then I suspect the OP didn't make this difference and passed "*.o" as the format instead of say, ELF. I've seen people do this before; just making sure it's not the case.

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Bogdan


Mon Oct 26, 2009 7:37 am
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Joined: Sat Jul 25, 2009 6:10 am
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Post Re: *.o not recongised: file format not recognised
Please stop arguing about the way I code please. :P

Code:
gcc -c  -nostartfiles -nostdlib -nostdinc -I ../include ../kernel/main.c -o kernel.o
nasm -f aout ../kernel/start.asm -o start.o
ld -T link.ld -o kernel.sys start.o kernel.o

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Michael Sammels

OS Developing is 10% luck, 20% skill, 15% concentrated power of will. 5% pleasure, 50% pain, and a 100% reason continue the game.


Mon Oct 26, 2009 11:50 am
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Joined: Sat Jul 25, 2009 11:26 am
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Post Re: *.o not recongised: file format not recognised
We weren't arguing. What was GCC configured for? If it was configured for ELF then you're trying to link an a.out with an ELF which will never work. Also, "-nostartfiles" means "-nostdlib" + "-nostdinc".

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Bogdan


Mon Oct 26, 2009 8:43 pm
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Post Re: *.o not recongised: file format not recognised
Hmm, you know I didnt think of that Bogdan.

Michael mate, build a cross-compiler for your platform, do both GCC and BinUtils so you know they will work together, there is a tutorial on OSDev.org on how to do this.

I used to have this same problem when I used DJGPP, but the actual error was a bit more obscure then yours, but it boiled down to the same problem.

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Kieran C G Foot


Tue Oct 27, 2009 4:54 am
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