A MEX-file lets you call a Fortran subroutine from MATLAB. To create a MEX-file, you need:
The ability to write Fortran source code. You can create these files with the MATLAB Editor.
A compiler supported by MATLAB. For an up-to-date list of supported compilers, see the Supported and Compatible Compilers website.
The mex build script. For more information, see Executable Fortran MEX-Files.
For information about writing C/C++ MEX-files, see C/C++ Source Files.
For information about using the loadlibrary and calllib commands to call functions in shared libraries, see Call C Shared Libraries.
MEX-files are not appropriate for all applications. MATLAB is a high-productivity environment whose specialty is eliminating time-consuming, low-level programming in compiled languages like Fortran. In general, do your programming in MATLAB. Do not use MEX-files unless your application requires it.