Show Symbol Table for OMF (.obj)?

Show Symbol Table for OMF (.obj)?

[Benjamin Cao]

Hi,

I am curious to know if there is a command that will display a symbol table for *.obj files. It seems as if commands such as "nm" or "objdump" do not do this. I get "File format not recognized".

If there is a way to get it to work with nm or objdump, I am all ears. Or if there is a different command to satisfy this, that would be helpful as well.

Thanks,
Ben Cao

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Re: Show Symbol Table for OMF (.obj)?

[Mark Geisert]

Benjamin Cao writes:
> I am curious to know if there is a command that will display a symbol 
table for *.obj files. It seems as if
> commands such as "nm" or "objdump" do not do this. I get "File format 
not recognized".
> 
> If there is a way to get it to work with nm or objdump, I am all ears. 
Or if there is a different command to satisfy
> this, that would be helpful as well.

Both nm and objdump are capable of displaying symbol tables.  The error 
message you're getting means you need to explicitly specify
"--target=BFDNAME" with BFDNAME matching the .obj file's format.

The formats we typically see are pe-i386 and pei-i386 for x86 object and 
image, and pe-x86-64 and pei-x86-64 for x86_64 object and image, 
respectively.

'nm --help' and 'objdump --help' show the supported targets.

..mark


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Re: Show Symbol Table for OMF (.obj)?

[Warren Young]

On May 16, 2016, at 1:10 PM, Benjamin Cao <becao@progress.com> wrote:
> 
> I am curious to know if there is a command that will display a symbol table for *.obj files. It seems as if commands such as "nm" or "objdump" do not do this. I get "File format not recognized”.

nm *is* the right tool, but only for file types it knows about.

You should only expect a platform’s native nm to support the native executable types of the platform it runs on.  In the case of Cygwin, that’s various flavors of COFF and PE.  OMF is an entirely different format.

Cygwin’s nm happens to also support ELF for some reason, but that is yet a third object format.

Assuming libbfd knows OMF, you could rebuild your own OMF cross-development toolchain.  Then *its* nm would be the right tool for the job.

  https://en.wikipedia.org/wiki/Binary_File_Descriptor_library
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Re: Show Symbol Table for OMF (.obj)?

[Yaakov Selkowitz]

On 2016-05-16 14:10, Benjamin Cao wrote:
> I am curious to know if there is a command that will display a symbol table for
> *.obj files. It seems as if commands such as "nm" or "objdump" do not do this.
> I get "File format not recognized".

You may want to try i586-pc-msdosdjgpp-{nm,objdump} from the 
djgpp-binutils package.

-- 
Yaakov

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Re: Show Symbol Table for OMF (.obj)?

[Hans-Bernhard Bröker]

Am 16.05.2016 um 22:05 schrieb Yaakov Selkowitz:
> On 2016-05-16 14:10, Benjamin Cao wrote:
>> I am curious to know if there is a command that will display a symbol
>> table for
>> *.obj files. It seems as if commands such as "nm" or "objdump" do not
>> do this.
>> I get "File format not recognized".

> You may want to try i586-pc-msdosdjgpp-{nm,objdump} from the
> djgpp-binutils package.

That won't help, because DJGPP uses COFF, not OMF.

Actually, I don't think binutils ever supported OMF.


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