MATLAB: Plot from C Mex function and C types

dwork vectorsmexmexcallmatlabplots-functionsimulink

Hello,
I'am writing an S-function in C and I need at some point to plot the content of DWork vectors (the first Dwork vector being the x-axis and the second the y-axis).
I tried the following:
    mexCallMATLAB(0,x,1,y,"plot");
However this doesn't work because x and y are not of type mxArray but REAL T. Indeed this is how x and y are defined:
    real_T *x = (real_T*) ssGetDWork(S,0);
    real_T *y = (real_T*) ssGetDWork(S,1);
It is not possible to change the type of x and y. Is it possible to copy the content of x and y in a mxArray so that the function mexCallMATLAB can be used? I am not really an expert in C, so hopefully it won't be too hard to implement 😮
Besides, is it possible to save the content of a Dwork vector (or a mxArray once "converted") in the Matlab workspace ?
Thanks.

Best Answer

I would recommend looking at the documentation for mxCreateDoubleMatrix, particularly the examples listed at the bottom of the page, to understand how you can copy over your data into an mxArray.
However, I'm not sure why you'd want to call the PLOT command from within the S-function. Why not just mark your DWorks as discrete states using ssSetDWorkUsedAsDState and select the Save to Workspace options on the Data Import/Export pane of the Configuration Parameters dialog box - this will log the state values to the workspace at the end of simulation, at which point you can use the block's StopFcn callback to automatically plot the data at the end of simulation.
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