Write C++ Functions Callable from MATLAB (MEX Files) - MATLAB & Simulink (original) (raw)

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Create high-performance functions, implemented in modern C++, that can be called from MATLAB®

Use the C++ MEX API to create MATLAB functions that provide the efficiency of C++ programs and that can access external functions and libraries from MATLAB. The C++ MEX API provides these features:

• Uses modern C++ programming features and object-oriented designs.
• Calls MATLAB functions from the MEX function.
• Integrates seamlessly into MATLAB, getting inputs from and returning results to MATLAB.
• Supports MATLAB data types and copy-on-write semantics.
• Writes thread-safe multi-threaded MEX functions.
• Executes C++ MEX functions out-of-process.

Note

Functions in the MATLAB C++ APIs use the matlab::data::Array class defined in the MATLAB Data API for C++. If your MEX functions must run in MATLAB R2017b or earlier, or if you prefer to work in the C language, then use the C Matrix API, which works with the mxArray data structure instead. For more information, see Write C Functions Callable from MATLAB (MEX Files).

Build Function

C++ Classes

Out-of-Process Execution

Topics

Create C++ MEX Functions

• C++ MEX Functions
  MEX files implement MATLAB functions written in C++.
• Create a C++ MEX Source File
  How to create a basic C++ MEX function.

Setup and Build MEX Files

• Build C++ MEX Programs
  Build MEX applications on different platforms.
• Test Your Build Environment
  Test your build environment with a predefined C++ MEX file.
• C++ MEX API
  Use C++11 features and the C++ Engine API to implement MEX functions.

Design of C++ MEX Functions

• Structure of C++ MEX Function
  Implement a class that overrides the function call operator() to create a functor object.
• Avoid Copies of Arrays in MEX Functions
  Techniques to avoid making copies of large arrays to reduce memory usage and improve execution speed.
• Manage External Resources from MEX Functions
  Customize the MexFunction class to better handle the resources used by your MEX function.
• Handle Inputs and Outputs
  Check the size and type of inputs and display error messages in MATLAB.
• Display Output in MATLAB Command Window
  MEX functions can display output in the MATLAB command window.
• Make async Requests Using mexCallMATLAB
  Behavior when calling back into MATLAB with an async request likematlab::engine::MATLABEngine::fevalAsync.
• Access ArgumentList and MATLAB Engine in User C++ Files
  How to compile matlab::mex::ArgumentList outside of MATLAB and link a shared library that uses MATLAB Engine API to a C++ MEX.

MATLAB Data Types in MEX Functions

• Data Access in Typed, Cell, and Structure Arrays
  Cell and structure arrays let you write to array contents without copying entire array.
• Data Types for Passing MEX Function Data
  Define the correct data types to pass data between MATLAB and MEX functions.

Call MATLAB Functions

• Call MATLAB Functions from MEX Functions
  Call MATLAB functions, passing arguments from and returning arguments to a MEX function.
• Catch Exceptions in MEX Function
  Catch exceptions thrown in a MEX function.
• Execute MATLAB Statements from MEX Function
  Execute MATLAB statements to create variables in the caller's workspace.

Separate Threads and Processes

• Call MATLAB from Separate Threads in MEX Function
  MEX functions can call MATLAB from user-created threads using the C++ Engine asynchronous API.
• Out-of-Process Execution of C++ MEX Functions
  Execute C++ MEX functions in processes that are separate from the MATLAB process.

Access MATLAB Variables

• Set and Get MATLAB Variables from MEX
  Put variables into or get variables from the MATLAB base and global workspaces.
• MATLAB Objects in MEX Functions
  Pass MATLAB objects to MEX functions.
• Use MEX Functions for MATLAB Class Methods
  You can use MEX functions to implement methods for MATLAB classes.

Related Information

• MATLAB Data API for C++
• Call MATLAB from C++

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