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.

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, 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:

  • Configure C++ Class Interface button

  • 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.

Command-Line Information

Parameter: CodeInterfacePackaging

Type: character vector

Value: 'C++ class' | 'Nonreusable function' | 'Reusable function'

Default: 'Nonreusable function' if TargetLang is set to 'C'; 'C++ class' if TargetLang is set to 'C++'

Recommended Settings

Application	Setting
Debugging	No impact
Traceability	No impact
Efficiency	Reusable function or C++ class
Safety precaution	No impact