roll back slbuild genrated model by one step

I have generated a Simscape model to c excutable and code using slbuild and it has produced a main code rt_malloc_main in C which I am editing. I will eventually build that executable with gcc (and where needed g++) and use in Ubuntu 22.04.

For various reasons I need to roll back the model, i.e. reject all the progress made during the last call to rt_OneStep(S). This is a large model with many simscapep multibody library blocks, but also simulink blocks, and some matlab function blocks which use global variables through the persistent command.

What I ideally want would look like this:

save model S

advance one step: rt_OneStep(S)

if condition is not achieved completely roll back everything to how they where before rt_OneStep was called, or in the very least time and states so that a new call to rt_OneStep would give the exact same results: restore(S)

I currently have some ad-hoc lines of code to do save and restore and various efforts have also led me to use the rt_terminate (S) and rt_Init(S) to avoid bad memory allocation problems, and then use restore(S) in the hope that I also change my time and all states in the various blocks.

Is there a formal way to go back one step and cancel the effects of rt_OneStep(S) without starting the simulation from t=0?

The reason behind this roll back is that I am coupling this code with another code that needs the roll-back

[sneha]

Hello,

there is no formal MathWorks-supported API to roll back a Simscape model one step in generated C code, because SimState and operating-point features are not supported for code generation with Simscape; the only reliable approach is to manually save and restore all simulation state memory before calling rt_OneStep(S), including continuous states (X), discrete work vectors (DW), mode vectors, zero-crossing signals, solver workspaces, timing fields, and Simscape internal runtime structures.

relevant MathWorks documentation:

Data Structures in the Generated Code: https://www.mathworks.com/help/rtw/ug/data-structures-in-the-generated-code.html

Access Block Data During Simulation: https://www.mathworks.com/help/simulink/ug/accessing-block-data-during-simulation.html

About Simscape Run-Time Parameters: https://www.mathworks.com/help/simscape/ug/about-simscape-run-time-parameters.html

Save State Information (Simulink): https://www.mathworks.com/help/simulink/ug/save-state-information.html

[E_C]

Thanks for teh suggestion I believe I am restoring almost all of the above but I am not sure what is the name to use for saving and restoring Simscape internal runtime structures

e.g. for continuoustates I can for example access them as: S->contStates (S is my model)

[E_C]

And perhaps if there is some guidance of what elements of DW (dwork) need to be saved and restored or how to configure slbuild to group them in a conveninent way to do so that would be very useful as a shallow copy of those doesn't seem to work (memcpy)