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
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
codegen -config:lib -lang:c++ foo
In the configuration object, set the
TargetLangparameter 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:
Generate C++ classes for classes in your MATLAB code.
Generate entry-point functions as methods in a C++ class.
Generate C++ namespaces for MATLAB packages. Place all generated code in a namespace that you specify. Place all code generated for MathWorks® code in a namespace that you specify.
Pass dynamically allocated arrays between your custom C++
code and the generated code. The generated C++ code implements
such arrays by using the
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
myTypecan appear in two different namespaces hierarchies with top-level namespaces
myNamespace_2. The C language does not support namespaces and such reuse of identifier names.
In generated C code, the function headers contain
#ifdef __cplusplusinclude 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
.cppfile extensions for the C++ files and
.hextensions for the header files. Generated C code uses
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
NaNbased 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 the Language Standard.