MATLAB: MATLAB appcrash when I use mxFree in S-Function

mxfrees-function

hi, I'm studying a C mex s-function. I wrote following C++ code.
#define S_FUNCTION_NAME    sfun_exam
#define S_FUNCTION_LEVEL  2
#include "simstruc.h"
#include "matrix.h" // for mxMalloc
#include <stdlib.h>
#define FALSE      0
#define TRUE      1
#define NUM_INPUTS    0
#define NUM_OUTPUTS    0
#define NUM_PARAMS    0
#define NUM_CONT_STATE  0
#define NUM_DISC_STATE  0
static void mdlInitializeSizes(SimStruct *S)
{
  ssPrintf("mdlInitializeSizes entry\n");
  ssSetNumSFcnParams(S, NUM_PARAMS);
  //ssSetSFcnParamTunable(S, 0, 0);
  ssSetNumContStates(S, NUM_CONT_STATE);
  ssSetNumDiscStates(S, NUM_DISC_STATE);
  if (!ssSetNumInputPorts(S, NUM_INPUTS)) return;
  
  if (!ssSetNumOutputPorts(S, NUM_OUTPUTS)) return;
  ssSetNumSampleTimes(S, 1);
  ssSetNumRWork(S, 0);
  ssSetNumIWork(S, 0);
  ssSetNumPWork(S, 1);
  ssSetNumModes(S, 0);
  ssSetNumNonsampledZCs(S, 0);
  ssSetSimStateCompliance(S, USE_DEFAULT_SIM_STATE);
  ssSetOptions(S, 0);
  ssPrintf("mdlInitializeSizes exit\n");
}
static void mdlInitializeSampleTimes(SimStruct *S)
{
  ssPrintf("mdlInitializeSampleTimes entry\n");
  ssPrintf("mdlInitializeSampleTimes exit\n");
}
#define MDL_START
static void mdlStart(SimStruct *S)
{
  ssPrintf("mdlStart entry\n");
  double  *temp = (double *)mxMalloc(sizeof(double));
  ssPrintf("assigned address = %d\n", temp);
  ssGetPWork(S)[0] = (void *)temp;
  ssPrintf("mdlStart exit\n");
}
static void mdlOutputs(SimStruct *S, int_T tid)
{
  ssPrintf("mdlOutputs entry\n");
  UNUSED_ARG(tid);
  ssPrintf("mdlOutputs exit\n");
}
static void mdlTerminate(SimStruct *S)
{
  ssPrintf("mdlTerminate entry\n");
  void  *temp;
  temp = ssGetPWork(S)[0];
  ssPrintf("assigned address = %d\n", temp);
  mxFree(temp);
  ssPrintf("mdlTerminate exit\n");
}
/*=============================*
 * Required S-function trailer *
 *=============================*/
#ifdef  MATLAB_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
It is built without error. but during simulation, MATLAB appcrash occured.
Problem signature
Problem Event Name:  APPCRASH
Application Name:  MATLAB.exe
Application Version:  7.13.0.0
Application Timestamp:  4e4754eb
Fault Module Name:  StackHash_b9f6
Fault Module Version:  6.1.7601.17725
Fault Module Timestamp:  4ec49b60
Exception Code:  c0000374
Exception Offset:  000c380b
OS Version:  6.1.7601.2.1.0.256.48
Locale ID:  1042
Additional Information 1:  b9f6
Additional Information 2:  b9f67d14f6a48d7204fa389a0a5bf0d1
Additional Information 3:  c4cc
Additional Information 4:  c4ccbe39e350b9853267802fd89da65d
When I used malloc and free Instead of mxMalloc and mxFree, this appcrash didn't occur.
what did I do wrong??
thanks for reading..

Best Answer

Hi,
please do not use mxfree and other mx* memory functions:
http://www.mathworks.com/support/solutions/en/data/1-5RMJID/?solution=1-5RMJID
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