Code interface packaging

Description

Select the packaging for the generated C or C++ code interface.

Category: Code Generation > Interface

Settings

Default: Nonreusable function if parameter Language is set to C; C++ class if Language is set to C++

C++ class

Generate a C++ class interface to model code. The generated interface encapsulates required model data into C++ class attributes and model entry point functions into C++ class methods.

For a model configured with a service interface, this parameter setting is not relevant and, therefore, is not supported.

Nonreusable function

Generate nonreusable code. Model data structures are statically allocated and accessed by model entry point functions directly in the model code.

Reusable function

Generate reusable, multi-instance code that is reentrant, as follows:

For a GRT-based model, the generated model.c source file contains an allocation function that dynamically allocates model data for each instance of the model. For an ERT-based model, you can use parameter Use dynamic memory allocation for model initialization to control whether an allocation function is generated.
The generated code passes the real-time model data structure in, by reference, as an argument to model_step and the other model entry point functions.
The real-time model data structure is exported with the model.h header file.

For an ERT-based model,

If the model is configured with a service interface, this setting is not supported.
You can use parameter Pass root-level I/O as to control how root-level input and output arguments are passed to the reusable model entry-point functions. They can be included in the real-time model data structure that is passed to the functions, passed as individual arguments, or passed as references to an input structure and an output structure.

Tips

Entry points are exported with model.h. To call the entry-point functions from handwritten code, add an #include model.h directive to the code.
When you select Reusable function, the code generator generates a pointer to the real-time model object (model_M).
When you select Reusable function, the code generator can generate code that compiles but is not reentrant. For example, if a signal, DWork structure, or parameter data has a storage class other than Auto, global data structures are generated.

Dependencies

The value C++ class is available only if parameter Language is set to C++.
Selecting Reusable function or C++ class enables parameter Multi-instance code error diagnostic.
For an ERT-based system target file, selecting Reusable function enables parameters Pass root-level I/O as and Use dynamic memory allocation for model initialization.
To enable parameter Classic call interface, select Nonreusable function.
For an ERT-based system target file, selecting C++ class enables the following model configuration controls for customizing the model class interface:
- Data Member Visibility/Access Control subpane
- Parameters Generate destructor and Use dynamic memory allocation for model block instantiation
For an ERT-based system target file, you can select Reusable function with the static ert_main.c module, if you do the following:
- Set parameter Pass root-level I/O as to Part of model data structure.
- Select parameter Use dynamic memory allocation for model initialization.
For an ERT-based system target file, you cannot select Reusable function if you are:
- Customizing the model_step function prototype
- Selecting subsystem block parameter Function with separate data
- Using a subsystem that
  - Has multiple ports that share source
  - Has a port that is used by multiple instances of the subsystem and has different sample times, data types, complexity, frame status, or dimensions across the instances
  - Has output marked as a global signal
  - For each instance contains identical blocks with different names or parameter settings
Selecting Reusable function does not change the code generated for function-call subsystems.