Choosing MEX Applications

You can call your own C, C++, or Fortran programs from the MATLAB^® command line as if they were built-in functions. These programs are called MEX functions. MEX functions 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 C or C++. In general, do your programming in MATLAB. Do not use MEX files unless your application requires it.

To create a MEX function, write your program using MATLAB APIs, then build it using the mex command. The APIs provide these features:

• Call MATLAB functions from the MEX function.

• Integrate seamlessly into MATLAB, getting inputs from and returning results to MATLAB.

• Support MATLAB data types.

C++ MEX Functions

As of MATLAB R2018a, write your C++ MEX functions using these APIs, which support C++11 programming features. These APIs, based on the matlab::data::Array class, provide better type safety, array bounds checking, and support for modern C++ constructs to simplify coding.

• C++ MEX API

• MATLAB Data API for C++

For more information, see Write C++ Functions Callable from MATLAB (MEX Files).

C/C++ MEX Functions for MATLAB R2017b and Earlier

If your MEX functions must run in MATLAB R2017b or earlier, or if you prefer to work in the C language, then write your source files using functions in these libraries based on the mxArray data structure.

• C MEX API on Write C Functions Callable from MATLAB (MEX Files)

• C Matrix API

For more information, see Write C Functions Callable from MATLAB (MEX Files).

Caution

Do not mix functions in the C Matrix API with functions in the MATLAB Data API.

Fortran MEX Functions

To write Fortran MEX functions, use these APIs based on the mxArray data structure.

• Fortran MEX API

• Fortran Matrix API

For more information, see Write Fortran Functions Callable from MATLAB (MEX Files).

MEX Terms

MEX stands for MATLAB executable and has different meanings, as shown in this table.

MEX Term	Definition
source MEX file	C, C++, or Fortran source code file.
binary MEX file or MEX function	Dynamically linked subroutine executed in the MATLAB environment.
MEX API	Functions in the C MEX API and Fortran MEX API to perform operations in the MATLAB environment.
mex build script	MATLAB function to create a binary file from a source file.