在mdlinitialsizes, specify the number of DWork vectors using thessSetNumDWorkmacro. For example, to specify that the S-function contains two DWork vectors, use the command

ssSetNumDWork(S, 2);

虽然mdlinitialsizes方法告诉Simulink金宝app^®engine how many DWork vectors the S-function will use, the engine does not allocate memory for the DWork vectors, at this time.

S功能可以推迟指定DWORK向量的数量，直到可以通过传递值来获得有关S功能输入的所有信息动态式尺寸到ssSetNumDWorkmacro. If an S-function defers specifying the number of DWork vectors inmdlinitialsizes, it must provide amdlsetworkwidthsmethod to set up the DWork vectors.

If the S-function does not provide anmdlsetworkwidths方法，mdlinitialsizesmethod sets any applicable attributes for each DWork vector. For example, the following lines initialize the widths and data types of the DWork vectors initialized in the previous step.

sssetDworkWidth（s，0，2）;sssetDworkWidth（S，1，1）;sssetDworkDatatype（s，0，ss_double）;sssetDworkDatatype（S，1，ss_boolean）;

The following table lists attributes you can set for a DWork vector and shows an example of the macro that sets it. Seesssetdworkrtwstorageclassfor a list of supported storage classes.

在mdlStart，初始化应仅在仿真开始时设置的任何DWORD向量的值。使用ssgetDWorkmacro to retrieve a pointer to each DWork vector and initialize the values. For example, the followingmdlStartmethod initializes the first DWork vector.

静态void mdlStart（simStruct *s）{real_t *x =（real_t *）ssgetDwork（s，0）;/ *初始化第一个dwork vector */ x [0] = 0;x [1] = 2;}

The Simulink engine allocates memory for the DWork vector before calling themdlStartmethod. Because themdlStart方法在模拟开头仅调用一次，请勿将其用于数据或需要重新初始化的状态，例如，在重新确定包含S函数的残疾子系统时。

在mdlInitializeConditions，初始化需要在仿真中某些点重新初始化的任何DWORD向量的值。引擎执行mdlInitializeConditions在模拟的开头以及任何启用包含S函数的子系统的启用子系统。看到mdlStart在上一个步骤中的示例用于初始化DWork Vector值的命令。

在mdlOutputs,mdlupdate等等，使用ssgetDWorkmacro to retrieve a pointer to the DWork vector and use or update the DWork vector values. For example, for a DWork vector storing two discrete states, the followingmdlOutputs和mdlupdate方法计算输出并更新离散状态值。

先前定义的S功能U(element)as（*uptrs [element]）,A,B,C， 和D作为离散状态空间系统的状态空间矩阵。

/*功能：mdlOutputs =================================================== *摘要： *y = cx + du */ static void mdlOutputs（simStruct *s，int_t tid）{if（ssgetDworkUsageType（s，0）== ss_dwork_used_used_as_as_dstate）{real_t *y = y = ssgetOutputputputportorportrealSignal（s，0）;real_t *x =（real_t *）ssgetDwork（s，0）;InputRealPtrStype uptrs = ssgetInputporterSignalPtrs（s，0）;Unused_arg（tid）;/*未在单个任务模式中使用*//*y = cx+du*/ y [0] = c [0] [0]*x [0]+c [0] [1] [1]*x [1]+d [0] [0]*u（0）+d [0] [1]*u（1）;y [1] = c [1] [0]*x [0]+c [1] [1]*x [1]+d [1] [0]*u（0）*u（0）+d [1] [1] [1]]*u（1）;}} #define mdl_update /*函数：mdlupdate ======================================================== *摘要： * xdot = ax + bu */ static void mdlupdate（simStruct * s，int_t tid）{real_t tempx [2] = {0.0，0.0，0.0};real_t *x =（real_t *）ssgetDwork（s，0）; InputRealPtrsType uPtrs = ssGetInputPortRealSignalPtrs(S,0); UNUSED_ARG(tid); /* not used in single tasking mode */ /* xdot=Ax+Bu */ tempX[0]=A[0][0]*x[0]+A[0][1]*x[1]+B[0][0]*U(0)+B[0][1]*U(1); tempX[1]=A[1][0]*x[0]+A[1][1]*x[1]+B[1][0]*U(0)+B[1][1]*U(1); x[0]=tempX[0]; x[1]=tempX[1]; }