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C++ Code Generation

MATLAB® Coder™ enables you to either generate C or C++ code. The code generator produces C code by default. Generated C++ code can use functionality not available in the C language that can make the C++ code more readable and easier to use.

Generate C++ Code

To generate C++ code, follow the same overall workflow steps that you use to generate C code. For example, see Generate C Code at the Command Line. Select the C++ language option from the command line, or with a code generation configuration setting, or from the MATLAB Coder app.

Suppose that you want to generate C++ code for a function foo that accepts zero inputs:

  • From the command line, use the -lang:c++ specifier. This specifier provides a quick and easy way to generate C++ code. For example, to generate a C++ static library and C++ source code for foo, enter:

    codegen -config:lib -lang:c++ foo
  • In the configuration object, set the TargetLang parameter to C++. For example, to generate a C++ dynamic library, enter:

    cfg = coder.config('dll');
    cfg.TargetLang = 'C++'; 
    codegen -config cfg foo 
  • From the app, at the Generate Code step, select the C++ language button.

C++ Language Features Supported in Generated Code

To learn about code generation that utilizes key C++ language features, refer to these help topics:

GoalMore Information

Generate C++ classes for classes in your MATLAB code.

Generate C++ Classes for MATLAB Classes

Generate entry-point functions as methods in a C++ class.

Generate C++ Code with a Class Interface

Generate C++ namespaces for MATLAB namespaces. Place all generated code in a C++ namespace that you specify.

Organize Generated C++ Code into Namespaces

Pass dynamically allocated arrays between your custom C++ code and the generated code. The generated C++ code implements such arrays by using the coder::array class template. The generated code provides a simple API that you can use to interact with this template.

Use Dynamically Allocated C++ Arrays in Generated Function Interfaces

These examples illustrate the use of these functionalities:

Additional Differences Between Generated C Code and C++ Code

If you separately generate C and C++ code for the same MATLAB function, and inspect the generated source code, then there are implementation differences. These are some notable differences:

  • The generated C++ code contains overloaded functions or methods that have the same name but support multiple signatures. The C language does not support overloading of functions.

  • The generated C++ code reuses the same identifier name across different namespace hierarchies. For example, the same type name myType can appear in two different namespaces hierarchies with top-level namespaces myNamespace_1 and myNamespace_2. The C language does not support namespaces and such reuse of identifier names.

  • In generated C code, the function headers contain #ifdef __cplusplus include guards that specify the extern "C" identifier for the generated C functions. The compiler and linker use these identifiers in building C code as part of a C++ project.

  • Generated C++ code uses .cpp file extensions for the C++ files and .h extensions for the header files. Generated C code uses .c and .h extensions.

  • The generated C++ code uses some C++ casts, like static_cast, which are more explicit than the casting syntax in C.

  • The generated code defines values for Inf and NaN based on different mechanisms for C++ and C.

  • Generated C++ code uses the custom data types as described in Mapping MATLAB Types to Types in Generated Code.

  • Generated C++ code uses different libraries than generated C code. For example, the default language standard for C++ and C is described in Change Language Standard Used for Code Generation.

See Also

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