error during mex compilation.

MAC osx vesion 10.10.2

xcode Version 6.2 (6C131e)

matlab version R2015a.

error message:

Error using mex
Undefined symbols for architecture x86_64:
  "_mexFunction", referenced from:
     -exported_symbol[s_list] command line option
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Does anyone know how to fix this issue?

Thanks.

[Ken Atwell]

Can you upload the file you are MEX'ing and tell us the command line you are using? Does that file in mexFunction() -- it need to.