Generate C++ Class Interface to Model or Subsystem Code

To generate a C++ class interface to model code, set model configuration parameter Code interface packaging (component) to C++ class. The generated interface encapsulates required model data into C++ class attributes and model entry point functions into C++ class methods. The benefits of C++ class encapsulation include:

  • Greater control over access to model data

  • Ability to create multiple instances of model classes

  • Easier integration of model code into C++ programming environments

Generate C++ Class Interface to Model Code

To generate encapsulated C++ class code from a model:

  1. Set model configuration parameter Language to C++. This selection also enables C++ class code interface packaging for the model.

  2. Verify that model configuration parameter Code interface packaging is set to C++ class.

  3. Examine the setting of Multi-instance code error diagnostic . Leave the parameter at its default value Error unless you need to alter the severity level for diagnostics displayed when a model violates requirements for generating multi-instance code.

  4. Generate code for the model.

  5. Examine the C++ model class code in the generated files model.h and model.cpp. For example, the following code excerpt from the H file generated for the example model SecondOrderSystem shows the C++ class declaration for the model.

    /* Class declaration for model SecondOrderSystem */
class SecondOrderSystemModelClass {
  /* public data and function members */
 public:
  /* External outputs */
  ExtY_SecondOrderSystem_T SecondOrderSystem_Y;

  /* Model entry point functions */

  /* model initialize function */
  void initialize();

  /* model step function */
  void step();

  /* model terminate function */
  void terminate();

  /* Constructor */
  SecondOrderSystemModelClass();

  /* Destructor */
  ~SecondOrderSystemModelClass();

  /* Real-Time Model get method */
  RT_MODEL_SecondOrderSystem_T * getRTM();
...
};

    For more information about generating and calling model entry-point functions, see Configure Generated C Function Interface for Model Entry-Point Functions.

Note

If you have an Embedded Coder® license and you have selected an ERT-based system target file for your model, use additional Code Generation > Interface pane parameters to customize the generated C++ class interface.

C++ Class Interface Limitations

  • Among the data exchange interfaces available on the Interface pane of the Configuration Parameters dialog box, only the C API interface is supported for C++ class code generation. If you select External mode or ASAP2 interface, code generation fails with a validation error.

  • If a model root inport value connects to a Simscape™ conversion block, you must insert a Simulink® Signal Conversion block between the root inport and the Simscape conversion block. On the Simulink Signal Conversion block parameter dialog box, select Exclude this block from 'Block reduction' optimization.

  • You cannot use a C++ class interface in cases when a referenced model cannot have a combined output/update function. Cases include a model that

    • Has a continuous sample time

    • Saves states

See Also

Topics