How can I dynamically grow the work vector in my level 2 MATLAB file S-function in Simulink 6.5 (R2006b)?

I want to implement a similar functionality as the Transport Delay block has in my level 2 MATLAB file S-function. So I need a buffer, but as I do not know the sample time for the model I do not know how to size my buffer. The Transport Delay block automatically increases the buffer size if needed, but the DWork vector dimensions are set once and are fixed.

Answer 1

[MathWorks Support Team]

The ability to change the dimension of the DWork vector for a level 2 MATLAB file S-function is not available in Simulink 6.5 (R2006b).

To work around this issue you can use one of the following approaches:

a. Make a worst-case estimation of how large your buffer needs to be and use this data for the DWork vector's dimension.

b. Use a C-MEX S-function instead of the MATLAB file S-function. In C-MEX you could use a PWork vector to keep a pointer to your buffer. In the beginning of your simulation you would allocate an initial buffer size. If your buffer is going to overflow you could re-allocate (realloc) the memory needed for the buffer.