how can i attain the obj file format??

Why do you want to attain the obj file format? Are you writing your own linker or your own debugger?

Please always write _long_and_detailed_ questions, since that affects the quality of any answers you may receive.

i just want to get the Relocation informations for functions in object module ,this can satisfy my requirements.

You still concentrated on the "what" and ignored the "why".