share memory address of variable among multiple s-functions

Hello, I am implementing a communication protocol using TCP socket in simulink. I use s-functions My initial idea is to define three C s-functions, that uses the same socket. 1. communication initialization, create a socket and get connected 2. a transmit block 3. a receive block I have included a header file defining some global variables that are necessary to all the three s-functions. I want the three s-function blocks are able to these variables (access to the same memory address) However, what I found is although I use the same header file, three s-functions create different variable instances. For example, I create the socket in the initialization s-function but this socket can not be used in the transmit and receive block.

So I wonder if there is any way we can share variables among different s-functions?

[Walter Roberson]

I suspect that you are implementing in C or C++?

[chong cao]

Yep it is in C/C++ S-FUNCTION

[Walter Roberson]

https://www.mathworks.com/help/ecoder/examples/configuring-the-data-interface.html seems to show examples of setting up global data; and https://www.mathworks.com/help/simulink/gui/simulink-coder-options.html and https://www.mathworks.com/help/simulink/ug/using-global-data-with-the-matlab-function-block.html

I seem to remember that some of the rest comes down to the code placement model properties that you define; it would take me a bit of time to find the settings.

Answer 1

[Qiu Xiaojie]

Hallo Chong,

Did you solve this problem? If you have any idea, please tell me how to share memory across several S-Function blocks.

Thank you!

[chong cao]

Hi, Xiaojie

This is solved by employing a dynamic link library (DLL). You can create a dll file by using the same compiler as you use in Matlab. You can just defiine the variable you need to share. Then call this dll in your s-functions.

Multiple s-function instances will visit this dll and update the variable.

That is how I solve this problem. There could be some other ways, but I use this.

Thanks

[Xiaojie Qiu]

Hi Chong,

Thank you very much for your answer! I solved this problem by using the method below:

https://de.mathworks.com/help/simulink/ug/incorporate-c-code-using-a-matlab-function-block.html

Best Regards