mex file error on mac, works on windows

I have downloaded a script and it works on a windows pc but on my macbook air (OSX10.8, matlab 2012b, xcode 4.6 with patch) it just won't work. Running the script does this:

Invalid MEX-file '/Users/Till/Documents/Arbeit/Forschung/Matlab/EVM_Matlab/matlabPyrTools/corrDn.mexmaci64':
dlopen(/Users/Till/Documents/Arbeit/Forschung/Matlab/EVM_Matlab/matlabPyrTools/corrDn.mexmaci64, 1): no suitable image found.  Did
find:
  /Users/Till/Documents/Arbeit/Forschung/Matlab/EVM_Matlab/matlabPyrTools/corrDn.mexmaci64: file too short

*Compiling the .c file:*

    >> mex -v corrDn.c

**************************************************************************
  Warning: Neither -compatibleArrayDims nor -largeArrayDims is selected. 
           Using -compatibleArrayDims. In the future, MATLAB will require
           the use of -largeArrayDims and remove the -compatibleArrayDims
           option. For more information, see:
           http://www.mathworks.com/help/techdoc/matlab_external/bsflnue-1.html
**************************************************************************

-> mexopts.sh sourced from directory (DIR = $PREF_DIR)
   FILE = /Users/Till/.matlab/R2012b/mexopts.sh
----------------------------------------------------------------
->    MATLAB                = /Applications/MATLAB_R2012b.app
->    CC                    = llvm-gcc-4.2
->    CC flags:
         CFLAGS             = -fno-common -no-cpp-precomp -arch x86_64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk/ -mmacosx-version-min=10.5  -fexceptions
         CDEBUGFLAGS        = -g
         COPTIMFLAGS        = -O2 -DNDEBUG
         CLIBS              = -L/Applications/MATLAB_R2012b.app/bin/maci64 -lmx -lmex -lmat -lstdc++
         arguments          =  -DMX_COMPAT_32
->    CXX                   = llvm-g++-4.2
->    CXX flags:
         CXXFLAGS           = -fno-common -no-cpp-precomp -fexceptions -arch x86_64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk/ -mmacosx-version-min=10.5
         CXXDEBUGFLAGS      = -g
         CXXOPTIMFLAGS      = -O2 -DNDEBUG
         CXXLIBS            = -L/Applications/MATLAB_R2012b.app/bin/maci64 -lmx -lmex -lmat -lstdc++
         arguments          =  -DMX_COMPAT_32
->    FC                    = gfortran
->    FC flags:
         FFLAGS             = -fexceptions -m64 -fbackslash
         FDEBUGFLAGS        = -g
         FOPTIMFLAGS        = -O
         FLIBS              = -L/Applications/MATLAB_R2012b.app/bin/maci64 -lmx -lmex -lmat -L -lgfortran -L -lgfortranbegin
         arguments          =  -DMX_COMPAT_32
->    LD                    = llvm-gcc-4.2
->    Link flags:
         LDFLAGS            = -Wl,-twolevel_namespace -undefined error -arch x86_64 -Wl,-syslibroot,/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk/ -mmacosx-version-min=10.5 -bundle -Wl,-exported_symbols_list,/Applications/MATLAB_R2012b.app/extern/lib/maci64/mexFunction.map
         LDDEBUGFLAGS       = -g
         LDOPTIMFLAGS       = -O
         LDEXTENSION        = .mexmaci64
         arguments          = 
->    LDCXX                 = 
->    Link flags:
         LDCXXFLAGS         = 
         LDCXXDEBUGFLAGS    = 
         LDCXXOPTIMFLAGS    = 
         LDCXXEXTENSION     = 
         arguments          = 
----------------------------------------------------------------

-> llvm-gcc-4.2 -c  -I/Applications/MATLAB_R2012b.app/extern/include -I/Applications/MATLAB_R2012b.app/simulink/include -DMATLAB_MEX_FILE -fno-common -no-cpp-precomp -arch x86_64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk/ -mmacosx-version-min=10.5  -fexceptions  -DMX_COMPAT_32 -O2 -DNDEBUG  "corrDn.c"

-> llvm-gcc-4.2 -O -Wl,-twolevel_namespace -undefined error -arch x86_64 -Wl,-syslibroot,/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk/ -mmacosx-version-min=10.5 -bundle -Wl,-exported_symbols_list,/Applications/MATLAB_R2012b.app/extern/lib/maci64/mexFunction.map -o  "corrDn.mexmaci64"  corrDn.o  -L/Applications/MATLAB_R2012b.app/bin/maci64 -lmx -lmex -lmat -lstdc++

Undefined symbols for architecture x86_64:
  "_internal_reduce", referenced from:
      _mexFunction in corrDn.o
  "_internal_wrap_reduce", referenced from:
      _mexFunction in corrDn.o
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status

      mex: link of ' "corrDn.mexmaci64"' failed.

Error using mex (line 206)
Unable to complete successfully.

• I am definitely not an expert on this and I am lost! Any ideas for help?

Thanks in advance! ti*

Answer 1

[Jan]

The file corrDn.c calls the functions "internal_reduce" and "internal_wrap_reduce", but the corresponding function definitions are not found. Either they are located in another C-file, and then both C-files must appear in the arguments of the mex command. Or you do not have the corresponding files and asking the author is the best idea.

Answer 2

[TAB]

mex files are compiled binary code which are platform dependent. A mex file compiled for windows platform will not work on other.

See Build MEX-Files.

[Walter Roberson]

The trace above showed that building the mex failed:

Undefined symbols for architecture x86_64:
  "_internal_reduce", referenced from:
      _mexFunction in corrDn.o
  "_internal_wrap_reduce", referenced from:
      _mexFunction in corrDn.o

[t]

I can compile the .c file but not link it. How do I do that? mex...?

Answer 3

[t]

Thanks, I finally got it...!

[Hugo Sanabria]

Would you mind sharing how you solve it? I have a similar problem.

[XI ZHOU]

To Hugo: I have the same problem as above. What Jan said is right. The command "internal_reduce" and "internal_wrap_reduce" are functions defined in other C-files. So we need to call them in the code. Here is my code:

 mex -compatibleArrayDims corrDN.c convolve.c edges.c wrap.c

The command "internal_reduce" is defined in the file 'convolve.c', and the command "internal_wrap_reduce" is defined in the file 'wrap.c'. Another command in 'convolve.c' is defined in the 'edges.c'. That is why I added the three C-files in the code (they are all in the same directory). Then the problem should be fixed.