How can i save matlab struct / class on level 2 matlab s-function ( like pwork) ? level 2 matlab s-function 에서 구조체 저장하는 방법 (pwork 같이 )

Hi all,

I have project written by two version of language ( C or matlab )

And i'm trying to imigrate my project to simulink.

In C s-function, I save struct data in p-work vector simply,

but level2 matlab s-function has no feature like that.

Can you help me?

I think s-function will be more compatible with matlab, why is there a feature only in C?

Is it because of the simplicity of the C data structure?

thank you.

I had tried : https://kr.mathworks.com/matlabcentral/answers/163566-how-to-pass-structures-and-strings-to-level-2-s-function

How to use classes as Simulink lvl 2-M S-function custom-blocks? - MATLAB Answers - MATLAB Central

안녕하세요

저는 C / matlab 두가지 언어 버전으로 구현된 프로젝트를 시뮬링크로 이식하고자 합니다.

C s-function에서는 pwork로 간단하게 구조체를 저장할 수 있는데,

matlab s-function 에는 구조체를 저장할수 있는 쉬운 방법이 없는것 같아 질문드립니다.

도움을 받을 수 있을까요?

감사합니다.

Answer 1

[Broy]

Hi @승욱,

I understand you are trying to migrate your project from C and MATLAB code into Simulink but are facing an issue where Level-2 MATLAB S-functions lack a P-Work vector feature to store your structural data.

The P-Work vector in C is designed specifically to store pointers to custom C structures. Since MATLAB is a higher-level interpreted language that manages memory automatically, it does not use raw pointers.

To resolve the issue, I recommend using MATLAB System Block Instead of using a Level-2 MATLAB S-function.

Here are some useful Documentations regarding MATLAB System Block as shown below:

• https://www.mathworks.com/help/releases/R2025b/simulink/slref/matlabsystem.html
• https://www.mathworks.com/help/releases/R2025b/simulink/define-system-object-for-simulink.html

I hope this is helpful.

[승욱]

Thank you for answer @Broy!

I tried it, but my code allocate memory in InitializeConditions method.

And even if I try using system block, struct data in system block cannot be changed inside s-function.

I have tried many ways for persist memory, and i think the best way is using Matlab function block with persistent variable

[Haelee]

Hi 승욱,

Regarding your comment on the Answer, I assume you can also refer to this MATLAB Answers post: https://www.mathworks.com/matlabcentral/answers/27902-working-with-matlab-classes-in-the-level-2-matlab-s-functions

If you need further assistance, please consider contacting MathWorks Technical Support (https://www.mathworks.com/support/contact_us.html).

Thanks.

[승욱]

@Haelee

해결 되었습니다. 정말 감사합니다!!