Specify that an input port expects one-based indices
void ssSetOneBasedIndexInputPort(SimStruct *S, int_T pIdx)
Use this macro in mdlInitializeSizes to specify that port pIdx expects one-based index values. By setting this macro, the Simulink® software runs a diagnostic when it updates the diagram to check if the S-function input port expecting one-based indices is connected to a block that is producing zero-based indices. The Simulink software signals an error if it detects that the signal connected to this block is zero-based. Simulink blocks that can produce indices include the For Iterator and S-function blocks. If neither this macro nor ssSetZeroBasedIndexInputPort is invoked, the Simulink software does not run this diagnostic, even if the input port is connected to a block that produces indices.