MATLAB: Including source files in s-function gateway file

include sourcesimulink

I am attempting to "include" a "xxx.c" file in the top s-function file that gets compiled into a ".mexw32" file. The file has the normal boiler-plate functions in it like :

static void mdlInitializeSizes( SimStruct *S ) static void mdlInitializeSampleTimes( SimStruct *S )

Etc etc

At the top of the file it looks like:

#define S_FUNCTION_NAME s_simulation #define S_FUNCTION_LEVEL 2

/******************/ /* / / INCLUDED FILES / / / /*****************/

/* reference appropriate header files */ #include "../simulation.h"

#include "../ChekFile.c" #include "../ChekFile2.c"

The header file is part of the code that currently functions OK but the last two lines do not seem to get used because when I use "dumpbin" to look in the ".mexw32" file I can't find any of the subroutines and the size of the ".mexw32" file doesn't change no matter how big I make the code for the ChekFile.c subroutines. I put calls to the subroutines in some of the boiler-plate subroutines but there doesn't seem to be a reference to them in the final ".mexw32" file.

Best Answer

What dumpbin flags are you using to examine the MEX binary? I think dumpbin only displays exported functions from a DLL. Ordinarily, in a MEX-function, only the gateway function called mexFunction() is exported (the export keyword is added in mex.h). For S-functions, this is not so obvious because Simulink adds some additional instrumentation around the mdlXXX functions (this is in simulink.c, which is included at the end of all S-functions) and calls them from a mexFunction - thus, it does conform to the interface of any other MEX-function.

So if you have included source files in your S-function and are able to compile and run it successfully (I presume you already test this by calling them from one of the mdlXXX functions), you can rest assured that they have indeed been included in the MEX binary.

Related Solutions

MATLAB: Can I create a C++ MEX-file S-function

We officially support C++ MEX-file S-functions as of Simulink 4.0 (R12).

To view an example of how to do this, please type:

sfundemos

at the MATLAB Command Prompt. This will open sfundemos.mdl. This demo that ships with SIMULINK provides examples of how to write different types of S-Functions and includes a C++ example.

You can also take a look at chapter 4 of the "Writing S-function" manual which has a good description on writing C++ MEX-file S-functions.

When writing the S-function, declare the MEX Function as extern "C". The rest of the code that you write can all be in C++. For example:

 extern "C" 
 {
 void mexFunction(
     int nlhs_,
     mxArray *plhs_[],
     int nrhs_,
     const mxArray *prhs_[])
 {
   /* Body can use all C++ language features and file can be compiled with a
      C++ compiler
    */
 }
 }

Below is the 'Timestwo' example written as a C++ file. You can compile the file using the MEX command. Note that if you are using the Watcom compiler, you need to add the -DNO_BUILT_IN_SUPPORT_FOR_BOOL flag to your COMPFLAGS option in your options file.

If you are using MSVC 5.0, you do not need to add this flag. The C compiler will automatically know to compile it as C++ code using the mex command.

 /*
* TIMESTWO An example C-file S-function for multiplying an input by 2
*      
*      y  = 2*x
*   
*   See sfuntmpl.c for a general S-function template.
*
*   See also VSFUNC, DSFUNC, SFUNTMPL.
* 
*   Copyright (c) 1990-96 by MathWorks, Inc.
*   All Rights Reserved
*   $Revision: 1.1 $
*/
 #ifdef __cplusplus
     extern "C" {
 #endif
 #define S_FUNCTION_NAME timestwo_level1_cpp
 /* The following three lines are necessary for the WATCOM compiler
* only. You need to remove these lines for the MSVC compiler.
*/
 #ifndef COMPILER_SUPPORTS_BOOL
 typedef int bool;
 #endif
 #include "simstruc.h"
 /*
* mdlInitializeSizes - initialize the sizes array
*/
 static void mdlInitializeSizes(SimStruct *S)
 {
     ssSetNumContStates(    S, 0);   /* number of continuous states */
     ssSetNumDiscStates(    S, 0);   /* number of discrete states */
     ssSetNumInputs(        S, DYNAMICALLY_SIZED);   /* number of inputs */
     ssSetNumOutputs(       S, DYNAMICALLY_SIZED);   /* number of outputs */
     ssSetDirectFeedThrough(S, 1);   /* direct feedthrough flag */
     ssSetNumSampleTimes(   S, 1);   /* number of sample times */
     ssSetNumSFcnParams(    S, 0);   /* number of input arguments */
     ssSetNumRWork(         S, 0);   /* number of real work vector elements */
     ssSetNumIWork(         S, 0);   /* number of integer work vector elements */
     ssSetNumPWork(         S, 0);   /* number of pointer work vector elements */
 }
 /*
* mdlInitializeSampleTimes - initialize the sample times array
*/
 static void mdlInitializeSampleTimes(SimStruct *S)
 {
     ssSetSampleTime(S, 0, CONTINUOUS_SAMPLE_TIME);
     ssSetOffsetTime(S, 0, 0.0);
 }
 /*
* mdlInitializeConditions - initialize the states
*/
 static void mdlInitializeConditions(double *x0, SimStruct *S)
 {
 }
 /*
* mdlOutputs - compute the outputs
*/
 static void mdlOutputs(double *y, double *x, double *u, SimStruct *S, int tid)
 {
     class mul2 {
         double            *u;
         double            *y;
         int                width;
     public:
         mul2(double *u_i, double *y_i, int width_i) 
         {
             u = u_i;
             y = y_i;
             width = width_i;
         }
         void output(void) 
         {
             for (int i=0;i<width;i++)
             { 
                 *y++=2.0*(*u++); 
             }
         }
     };
     class mul2 m(u,y,ssGetNumOutputs(S));
     m.output();
 }
 /*
* mdlUpdate - perform action at major integration time step
*/
 static void mdlUpdate(double *x, double *u, SimStruct *S, int tid)
 {
 }
 /*
* mdlDerivatives - compute the derivatives
*/
 static void mdlDerivatives(double *dx, double *x, 
                            double *u, SimStruct *S, int tid)
 {
 }
 /*
* mdlTerminate - called when the simulation is terminated.
*/
 static void mdlTerminate(SimStruct *S)
 {
 }
 #ifdefMATLAB_MEX_FILE    /* Is this file being compiled as a MEX-file? */
 #include "simulink.c"      /* MEX-file interface mechanism */
 #else
 #include "cg_sfun.h"       /* Code generation registration function */
 #endif
 #ifdef __cplusplus
     }
 #endif

MATLAB: How to copy data to a new string variable in a C-MEX file

Use the mxArray* returned by the mxCreateString function to copy data to a new mxArray* as follows:

 #include "mex.h"
 void mexFunction( int nlhs, mxArray *plhs[],
                   int nrhs, const mxArray *prhs[] )
 {
 mxArray *origString, *userString;
 int arrayLen;
 /* Initialize */
 origString = mxCreateString("This is the primitive string");
 /* Copy values to new string */
 userString = origString;
 /* Determine array length */
 arrayLen = mxGetNumberOfElements(origString);
 printf("The array length is: %d \n", arrayLen);
 /* Remaining code is just for testing */
 plhs[0] = userString;
 return;
 }

To test the above mexFunction after building to a MEX file, for example mexFunction.mexw32, invoke:

y = mexFunction

Best Answer

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MATLAB: Can I create a C++ MEX-file S-function

MATLAB: How to copy data to a new string variable in a C-MEX file

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