User`s guide

3 Writing S-Functions As C-MEX files
3-66
matlabroot/simulink/src/mixedm.c
/* File : mixedm.c
* Abstract:
*
* An example C MEX S-function that implements a continuous integrator (1/s)
* in series with a unit delay (1/z)
*
* For more details about S-functions, see simulink/src/sfuntmpl.doc.
*
* Copyright (c) 1990-1998 by The MathWorks, Inc. All Rights Reserved.
* $Revision: 1.4 $
*/
#define S_FUNCTION_NAME mixedm
#define S_FUNCTION_LEVEL 2
#include "simstruc.h"
#define U(element) (*uPtrs[element]) /* Pointer to Input Port0 */
/*====================*
* S-function routines *
*====================*/
/* Function: mdlInitializeSizes ===============================================
* Abstract:
* The sizes information is used by Simulink to determine the S-Function
* block's characteristics (number of inputs, outputs, states, etc.).
*/
static void mdlInitializeSizes(SimStruct *S)
{
ssSetNumSFcnParams(S, 0); /* Number of expected parameters */
if (ssGetNumSFcnParams(S) != ssGetSFcnParamsCount(S)) {
return; /* Parameter mismatch will be reported by Simulink */
}
ssSetNumContStates(S, 1);
ssSetNumDiscStates(S, 1);
if (!ssSetNumInputPorts(S, 1)) return;
ssSetInputPortWidth(S, 0, 1);
ssSetInputPortDirectFeedThrough(S, 0, 1);
if (!ssSetNumOutputPorts(S, 1)) return;
ssSetOutputPortWidth(S, 0, 1);
ssSetNumSampleTimes(S, 2);
ssSetNumRWork(S, 0);
ssSetNumIWork(S, 0);
ssSetNumPWork(S, 0);
ssSetNumModes(S, 0);
ssSetNumNonsampledZCs(S, 0);