A MEX file is a function, created in MATLAB, that calls a C, C++, or Fortran subroutine. To call a MEX file, use the name of the file, without the file extension. The MEX file contains only one function or subroutine, and its name is the MEX file name. The file must be on your MATLAB path.
For information about creating MEX files, see C MEX Files.
For information about using MEX S-functions in models, see your Simulink® documentation.
For best results, run MEX files built with your MATLAB version.
If you get a binary MEX file from another source, be sure that the file was compiled for the same platform on which you want to run it.
What to do when you get an invalid MEX file error.