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Limitations to C/C++ Support

You can create a MATLAB® interface to shared libraries based on C++98 and commonly occurring C++11 features. However, if a library contains the following data types or language features, then the functionality is not included in the MATLAB interface to the library. You might be able to include this functionality by creating a wrapper header file. For more information, see C++ Limitation Workaround Examples.

Data Types Not Supported

  • Any type with a size greater than 64 bits, for example long double

  • void *

  • Arrays of character types (wchar_t, char16_t, char32_t)

  • Pointers or arrays of std::string

  • References to a pointer in a function

  • Pointers or references to enumerations

  • Reference data members

  • std smart pointers other than std::shared_ptr

  • Static data members

  • ** pointers to primitive types, such as double**. MATLAB supports ** pointers to custom classes used as function or ​method parameter types.

  • Multilevel pointers, such as type***

  • Function pointer

  • Class templates with incomplete or no instantiations

  • union

These types defined in the std namespace are supported. All other types in the std namespace are not supported.

  • std::string, std::wstring, std::u16string, std::u32string

  • std::vector

  • std::shared_ptr

If a library uses these data types, then the functionality is not included in the MATLAB interface to the library, and MATLAB displays messages like:

Did not add member 'methodName' to class 'ClassName' at HeaderFile.h:290.
  'long double' is not a supported type.

To view these messages, use the 'Verbose' option in the clibgen.generateLibraryDefinition or clibgen.buildInterface functions.

Language Features Not Supported

  • move constructor

  • Overloaded operator functions

  • Unnamed namespaces and classes

  • Macro constants

  • Global variables

  • Variadic functions

  • Function templates with incomplete or no instantiations

  • Creating objects of classes in std namespace, including custom classes.

  • Smart pointer semantics. Only std::shared_ptr is supported. MATLAB does not support operator overloads, move semantics, and the member functions in the class definition of the smart pointer which might restrict their effectiveness. Instead, a std::shared_ptr<T> behaves as type T in MATLAB. Type T can be passed as input for std::shared_ptr<T>, and type T is received as output for std::shared_ptr<T>.

  • Namespace aliases. Use original namespace name instead.

  • Certain class methods that have MATLAB names are not supported. These methods are eq, ne, lt, gt, le, and ge.

When you build a library containing these features or usage, MATLAB displays:

Warning: Some C++ language constructs in the header file are not supported and not imported.

Note

Saving C++ objects into a MAT-file is not supported.

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