MEX file
In computing, MEX stands for MATLAB Executable and is a type of Computer file. A MEX-file (also written as MEX file) provides an interface between MATLAB or GNU Octave and subroutines written in C, C++ or Fortran. When compiled, MEX files are dynamically loaded and allow non-MATLAB code to be invoked from within MATLAB or GNU Octave as if it were a built-in function. To support the development of MEX files, MATLAB and GNU Octave offer external interface functions that facilitate the transfer of data between MEX files and the workspace. GNU Octave however, has its own format using its own, native API, resulting in a better performance over a MEX file in GNU Octave.[1]