It is possible to have variable number of inputs and outputs for a S-Function. Please see the attached model "testsfcn.mdl". This model contains a S-Function named "testtimestwo". You need to take the number of input ports as a parameter from the S-Function and then set the number of inputs to this number. Please see the attached C-File "testtimestwo.c" which demonstrates the S-Function with variable number of inputs.
For example, you can execute the attached example by performing the following steps:
1. Download the attached MDL-file and C-file.
2. Compile the "testtimestwo.c" file using the following command
mex testtimestwo.c
3. Double-click the S-Function block in the model and enter the desired number of inputs.
You will notice that the number of inputs for the S-Function block changes to the desired number that was entered in step 3 above.
