How can I make const pointer in RT code generation?

I would like to create constant pointer to variable values to avoid putting the pointer to the RAM.

Are there settings available to achieve this?

[Gokul Karikkat Swamikuttan]

I have the same question

[Michael Kotthaus]

I think, I have the same question.

This is what I want to do:

• A Simulink block should generate a reusable C function.
• The inputs and outputs are provided to the function as pointers to structs.
• The input should be a read-only pointer which is expressed by the const qualifier.
• The output should be a normal pointer because the function has to write to pointer's target.

So, the function's prototype declaration should not look like this:

extern void filter_step(RT_MODEL_filter_T *const filter_M,
                        ExtU_filter_T *filter_U,
                        ExtY_filter_T *filter_Y);

It should look like this:

extern void filter_step(RT_MODEL_filter_T *const filter_M,
                        const ExtU_filter_T *filter_U, // const because read-only
                        ExtY_filter_T *filter_Y);

This is important to achieve https://isocpp.org/wiki/faq/const-correctness

Any ideas are welcome!

michaeL

Answer 1

[Yuxuan Hao]

Hi,

I am assuming you have embedded coder toolbox, and you can achieve it in the following way.

Step1. Open Embedded code mapping (by selecting embedded coder in app gallery)

Step2. In function section, click Function Preview of the step function you wish to customize.

Check Configure arguments for Step function prototype.

Then click Get Default button.

After that, you can select the style you want.

Here is a more detailed reference: https://www.mathworks.com/help/ecoder/ug/configure-c-code-generation-for-model-entry-point-functions.html#mw_6f25ec45-7299-4d8a-a2b9-0b0cbdb89cd4

Best regards,

Yuxuan