| Are an M programmer with little or no C programming experience | A Level-2 M-file S-function, especially if you do not need
to generate code for a model containing the S-function (see Writing S-Functions in M). |
| Need to generate code for a model containing the S-function | Either a Level-2 M-file S-function or a C MEX S-functions.
Level-2 M-file S-functions require that you write a Target Language
Compiler (TLC) file for your S-function, before generating code. C
MEX S-functions, however, automatically support code generation. |
| Need the simulation to run faster | A C MEX S-function, even if you do not need to generate code
(see Writing S-Functions in C).
For complicated systems, Level-2 M-file S-functions simulate slower
than C MEX S-functions because they call out to the MATLAB interpreter. |
| Need to implement the S-function in C, but have no previous
experience writing C MEX S-functions | The S-Function Builder. |
| Are incorporating legacy code into the model | Any S-function, with the exception of a Level-1 M-file S-function.
Consider using the Legacy Code Tool if your legacy function calculates
only outputs, not dynamic states (see Integrating Existing C Functions into Simulink Models
with the Legacy Code Tool). Otherwise, consider using the S-Function Builder.
If you need to call the legacy code during simulation, do not use
a Level-2 M-file S-function because they call legacy code only through
their TLC files. |
| Need to generate embeddable code for an S-function that incorporates
legacy code | The Legacy Code Tool if your legacy function calculates only
outputs. Otherwise, use a handwritten C MEX S-function or the S-Function
Builder. |
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