Problem using C file and Cocoa classes together

I have imported the ffmpeg and SDL libraries into my Xcode project for a Cocoa application. My project builds and runs successfully with these libraries when my project contains only Cocoa classes, but when I include a C file in my project, the build fails with one warning and 35 errors:

The warning is:

ld: warning: in /Developer/SDKs/MacOSX10.6.sdk/usr/lib/gcc/powerpc-apple-darwin10/4.2.1/libgcc.a, file was built for unsupported file format which is not the architecture being linked (x86_64)

and the errors:

 "___g开发者_运维问答edf2", referenced from:

     _eval_expr in libavcodec.a(eval.o)
     _quantize_lpc_coefs in libavcodec.a(lpc.o)
     _rc_2pass2_before in libxvidcore.a(plugin_2pass2.o)

 "___ledf2", referenced from:

         _qp2bits in libavcodec.a(ratecontrol.o)
         _get_qscale in libavcodec.a(ratecontrol.o)

 "___umodsi3", referenced from:
         _vorbis_parse_setup_hdr_codebooks in libavcodec.a(vorbis_dec.o)
         _vorbis_parse_setup_hdr_codebooks in libavcodec.a(vorbis_dec.o)

For running the code, these are the configuration settings:

• Active architecture: x86_64
• Architecture in project setting: Standard (32/64_bit universal)
• Mac OS X version: 10.6.3
• Xcode version: 3.2.3

Also, the same code is building and running successfully with the same settings on my other system, a Mac Mini.

If anyone has any idea what I am missing then please help. Thanks.

Read the error message carefully (emphasis mine):

ld: warning: in /Developer/SDKs/MacOSX10.6.sdk/usr/lib/gcc/powerpc-apple-darwin10/4.2.1/libgcc.a, file was built for unsupported file format which is not the architecture being linked (x86_64)

Looks like you're mixing PowerPC and Intel libraries somehow. You're compiling for x86_64 but you're picking up a libgcc.a for PowerPC.

Those symbols with all the leading underscores are probably supposed to come from libgcc.a but you're not linking the x86_64 version of libgcc.a so they're missing in action and chaos ensues. Sounds like something in your xcode configuration is confused.