title: How to set up a level 2 s function with no direct feedthrough?
body: <p>I have a Simulink model being compiled to an executable through Embedded Coder (RTW) and have an SFunction that I know has no connection between the input and output so would like to turn off direct feedthrough on its input port. I could in fact make two SFunctions to replace it, one with an input, one with an output, the only complication is the external system I am addressing does its two-way communication in a single function call.</p>
  
  <p>We currently use the Legacy Code Tool to compile all of our SFunctions, but this I have read and verified forces all inputs to be direct feedthrough whether they are or not (with no explanation of why.) I have had a look as the SFunction Builder block, however it makes no reference to direct feedthrough on inputs. I have also looked at the msfuntmpl_basic.m template  builder script however it seems to be limited to inputs and outputs with primitive data types (via the DatatypeID.)</p>