### A.2 Mex-Files

Octave includes an interface to allow legacy mex-files to be compiled and used with Octave. This interface can also be used to share compiled code between Octave and MATLAB users. However, as mex-files expose MATLAB’s internal API, and the internal structure of Octave is different, a mex-file can never have the same performance in Octave as the equivalent oct-file. In particular, to support the manner in which variables are passed to mex functions there are a significant number of additional copies of memory blocks when invoking or returning from a mex-file function. For this reason, it is recommended that any new code be written with the oct-file interface previously discussed.