clibgen.generateLibraryDefinition

Create definition file for C++ library

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Syntax

clibgen.generateLibraryDefinition(InterfaceGenerationFiles,Libraries=LibraryFiles)
clibgen.generateLibraryDefinition(InterfaceGenerationFiles,SupportingSourceFiles=SourceFiles)
clibgen.generateLibraryDefinition(InterfaceGenerationFiles)
clibgen.generateLibraryDefinition(___,Name=Value)

Description

The clibgen.generateLibraryDefinition function creates a definition file with a .m file extension used to generate a MATLAB® interface to a C++ library. Use this function to:

  • Select C/C++ files that define the interface. For guidance on which syntax to use, see "Files in Your Library" in Tips.

  • Select configurations used by the generate step.

  • Optionally specify configurations to use to define arguments.

  • Optionally specify compiler build configuration arguments.

After creating the definition file, you optionally can modify the contents to include functionality that the function cannot automatically define. For information about using a library definition file, see Define MATLAB Interface for C++ Library.

You need a C++ compiler that MATLAB supports. You must build the interface library using the same compiler that was used to build the C++ library. If your library is completely defined by source files (does not use a compiled library file), then you can choose any supported C++ compiler to build the interface library. For information about your C++ compilers, type:

mex -setup cpp

Call the build function on the definition file to create the MATLAB interface file.

clibgen.generateLibraryDefinition(InterfaceGenerationFiles,Libraries=LibraryFiles) creates a definition file defined by InterfaceGenerationFiles and LibraryFiles.

The name of the definition file is definelibName.m (since R2022b). By default, libName is the name of the first file specified in InterfaceGenerationFiles. For example, if you specify a header file named mylibrary.hpp, then the function creates a definition file named definemylibrary.m. If you specify more than one interface generation file, then you must use the InterfaceName name-value argument to specify libName.

example

clibgen.generateLibraryDefinition(InterfaceGenerationFiles,SupportingSourceFiles=SourceFiles) for a library defined by multiple header files, source files, and, if required, compiled library files.

clibgen.generateLibraryDefinition(InterfaceGenerationFiles) for a library completely defined by InterfaceGenerationFiles. If your library includes a compiled library file, then you must specify a Libraries argument.

example

clibgen.generateLibraryDefinition(___,Name=Value) creates the file using one or more name-value arguments. Use this option with any of the input argument combinations in the previous syntaxes.

Examples

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The files for this example are in a MATLAB examples folder. Generate the library definition file definematrixOperations.m from the matrixOperations.hpp header file on Windows®. For a Linux® example, see Header and C++ Compiled Library Files on Linux.

Create an InterfaceGenerationFiles argument hFile with the full path to the header file.

hFile = fullfile(matlabroot,"extern","examples","cpp_interface","matrixOperations.hpp");

The header file includes another header file. Create an IncludePath argument iPath with the full path to the folder containing the included header file.

iPath = fullfile(matlabroot,"extern","examples","cpp_interface");

Create a Libraries argument libFile with the full path to the compiled library file.

libFile = fullfile(matlabroot,"extern","examples","cpp_interface", ...
    "win64","mingw64","matrixOperations.lib");

Create the definematrixOperations.m library definition file.

clibgen.generateLibraryDefinition(hFile,IncludePath=iPath,Libraries=libFile)
C++ compiler set to 'MinGW64 Compiler (C++)'.
Definition file definematrixOperations.m contains definitions for 10 constructs supported by MATLAB.
- 5 constructs are fully defined.
- 5 constructs partially defined and commented out. 

To include the 5 undefined constructs in the interface, 
uncomment and complete the definitions in definematrixOperations.m.
To build the interface, call build(definematrixOperations).

The files for this example are in a MATLAB examples folder. Generate a library definition file named definematrixOps.m from the matrixOperations.hpp and matrixOperations.cpp files.

Create an InterfaceGenerationFiles argument hFile with the full path to the header file matrixOperations.hpp.

hFile = fullfile(matlabroot,"extern","examples","cpp_interface","matrixOperations.hpp");

The header file includes another header file. Create an IncludePath argument iPath with the full path to the folder containing the included header file.

iPath = fullfile(matlabroot,"extern","examples","cpp_interface");

Create a SupportingSourceFiles argument cFile with the full path to the C++ source file matrixOperations.cpp.

cFile = fullfile(matlabroot,"extern","examples","cpp_interface","matrixOperations.cpp");

Create the definematrixOps.m library definition file by setting the InterfaceName argument to "matrixOps".

clibgen.generateLibraryDefinition(hFile, ...
    SupportingSourceFiles=cFile, ...
    IncludePath=iPath, ...
    InterfaceName="matrixOps")
C++ compiler set to 'MinGW64 Compiler (C++)'.
Definition file definematrixOps.m contains definitions for 10 constructs supported by MATLAB.
- 5 constructs are fully defined.
- 5 constructs partially defined and commented out. 

To include the 5 undefined constructs in the interface, 
uncomment and complete the definitions in definematrixOps.m.
To build the interface, call build(definematrixOps).

Generate the library definition file defineschool.m from the school.hpp header file.

clibgen.generateLibraryDefinition(fullfile(matlabroot,"extern","examples", ...
    "cpp_interface","school.hpp"))
C++ compiler set to 'MinGW64 Compiler (C++)'.
Definition file defineschool.m contains definitions for 21 constructs supported by MATLAB.
- 20 constructs are fully defined.
- 1 construct partially defined and commented out.

To include the 1 undefined construct in the interface, 
uncomment and complete the definitions in defineschool.m.
To build the interface, call build(defineschool).

Input Arguments

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Files to generate the interface, specified as a string array, character vector, or cell array of character vectors. If not in the current folder or on your MATLAB path, then the argument includes the full or relative path to the file. For more information, see "Files in Your Library" in Tips.

Files for specifying InterfaceGenerationFiles and SupportingSourceFiles arguments are:

  • Header files, with file extensions .h, .hpp, or .hxx. A header file without an extension is also supported. If you set the CLinkage argument to true, then code in .h header files must be C++ compatible C code.

    If you specify more than one interface generation file, then you must use the InterfaceName argument.

  • Source code files, with file extensions .c, .cpp, or .cxx. For information about using C source files, see CLinkage.

These files must contain declarations of all the functions exported by the library. You should be able to compile them in a C++ development environment and use the functionality in C++ applications. If the library is completely defined by the header files (header-only library), then you do not need to specify the Libraries argument.

If the main header file contains #include statements for header files in different folders, then use the IncludePath argument to specify these paths.

If you provide a single header filename, then the function looks for a library with the same name, in the same folder as the header file. The library must have a platform-specific filename extension. If the library has a different name or is not in the same folder, then use the Libraries argument.

The function writes the interface files in a subfolder in the current folder, unless you specify the OutputFolder argument. The name of the subfolder is the name of the first header file without a file extension. For example, this statement creates the interface library file in the subfolder myHeader in the current folder.

clibgen.generateLibraryDefinition("myHeader.hpp")

Example: "sample.hpp"

Data Types: char | string | cell

Name-Value Arguments

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Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: clibgen.generateLibraryDefinition( ...
["hfile1.hpp","hfile2.hpp"], ...
Libraries="hfile1.lib", ...
IncludePath="C:\mylib\include", ...
InterfaceName="mylib", ...
OutputFolder="C:\work", ...
DefinedMacros=["mymacro1","mymacro2=0"], ...
UndefinedMacros="mymacro3", ...
OverwriteExistingDefinitionFiles=true);

File Selection

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Compiled library filenames, specified as a string array, character vector, or cell array of character vectors. This value is required except if the library is completely defined by the files specified by the InterfaceGenerationFiles argument and the SupportingSourceFiles name-value argument.

A library is one of these:

  • On Windows platforms:

    • For compiled libraries, specify a .lib import library file.

      If the .lib file is not available and the library is compiled with a supported Microsoft® Visual Studio® compiler, then you can specify a .dll dynamic-link library file (since R2021a). For example:

      clibgen.generateLibraryDefinition("A.hpp",Libraries="A.dll")

    • For static libraries, specify a .lib file. For example:

      clibgen.generateLibraryDefinition("A.hpp",Libraries="A.lib")

      If the library is compiled with a supported MinGW-w64 compiler, then you can specify a .a static library file (since R2022a). For example:

      clibgen.generateLibraryDefinition("A.hpp",Libraries="A.a")

  • On Linux platforms, specify a .so shared object file or a .a static library file.

  • On macOS platforms, specify a .dylib dynamic shared library file or a .a static library file.

For example, this statement creates definesample.m using sample.hpp in the current folder and myLib.lib in the C:\myLib folder and writes the definition file in the current folder.

clibgen.generateLibraryDefinition("sample.hpp",Libraries="C:\myLib\myLib.lib")

Data Types: char | string | cell

C/C++ source files, specified as a string array, character vector, or cell array of character vectors. Use with the SupportingSourceFiles name-value argument. Supported file extensions are .c, .cpp, and .cxx. If not in the current folder or on your MATLAB path, then the argument includes the full or relative path to the file. A supporting source file must contain C/C++ code.

For more information, see "Files in Your Library" in Tips.

For information about building C source files, see CLinkage.

If the library is completely defined by header and C++ source files, then compiled library files are not required.

Example: "sample.cpp"

Data Types: char | string | cell

Folders for included header files, specified as a string array, character vector, or cell array of character vectors. Each value in IncludePath must be the full pathname to folders to include during compilation of the header files.

If the main header file contains #include statements for header files in different folders, then use the IncludePath argument to specify these paths.

Data Types: char | string | cell

Since R2024a

Starting pathname for publishers who plan to share library definition files, specified as a scalar dictionary, where key is a variable name chosen by the publisher and value is a relative pathname. The dictionary entries are specified as string scalars or character vectors. For example, on your computer, the starting pathname to the library files is c:\user1\libname. Another publisher has the same library version located in folder c:\user2\libname. Choose a key variable name and pass that name to the other publisher, who uses it to identify their local folder in the clibgen.generateLibraryDefinition function.

Identify the local path to files specified in these arguments, and put the path in a RootPaths dictionary argument:

Then replace the local path in any of these argument names with the RootPaths key by using the < and > tags. This enables another publisher to specify their own local path in the RootPaths key-value argument which MATLAB uses to identify the path in these arguments. For example, these statements create a library definition file named definemyLib.m. The dictionary key is rootpath, and the library files are located on your computer in C:\user1\libname.

startpaths = dictionary;
startpaths("rootpath") = "C:\user1\libname\";
clibgen.generateLibraryDefinition( ...
    ["<rootpath>\src\header1.hpp" "<rootpath>\include\header2.hpp"], ...
    IncludePath="<rootpath>\include", ...
    Libraries="<rootpath>\lib\libname.lib", ...
    OutputFolder="<rootpath>\MATLAB", ...
    RootPaths=startpaths, ...
    InterfaceName="myLib");

If another publisher has the same version of the library in the same file structure, but under a root folder named C:\user2\libname, then you can give the publisher your definemyLib.m and myLibData.xml files with these instructions for building the interface.

libdef = definemyLib;
%myPath = location of files that define library in local folder
libdef.RootPaths("rootpath") = myPath;
libdef.build

Configuration

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Since R2024a

Generated interface namespace, specified as a string scalar or a character vector. For interfaces created from a single header file, the default value is the name of the header. For multiple header files, InterfaceName must be a valid MATLAB name.

For example, this statement creates definemylib.m in the current folder.

clibgen.generateLibraryDefinition(["h1.hpp","h2.hpp"],InterfaceName="mylib")

Use the InterfaceName to call the library from MATLAB. For example, to call function myfunc in library interface libname, type:

clib.libname.myfunc

For more information, see Call Functions in C++ Compiled Library.

Data Types: char | string | cell

Folder name for the generated definition file, specified as a string scalar or a character vector. Verify that the folder is on your MATLAB path before calling the build function. This statement creates definemyHeader.m in C:\work.

clibgen.generateLibraryDefinition("myHeader.hpp",OutputFolder="C:\work")

Data Types: char | string | cell

Since R2021b

Option to overwrite library definition files, specified as a numeric or logical 1 (true) or 0 (false). A definition file is of the form definelibName.m or definelibname.m. Set OverwriteExistingDefinitionFiles to true to overwrite the existing files. Use this option to regenerate the definition file.

Caution

When you use this option, the function deletes the files, including edits you might have made to the files.

Data Types: logical

Option to display generation messages, specified as a numeric or logical 1 (true) or 0 (false). If Verbose is true, then the function displays generation messages to the command window while creating the definition file and for the build command. This statement creates defineh1.m and displays messages to the command window.

clibgen.generateLibraryDefinition("h1.hpp",Verbose=true)

For more information, see Messages About Unsupported Types.

Data Types: logical

C++ Library Settings

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Since R2022a

Option to specify how to parse and build .h header files, specified as a numeric or logical 1 (true) or 0 (false).

If CLinkage is true, then the function treats .h header files in the InterfaceGenerationFiles argument as C header files. C header files are included with extern "C" blocks in the generated interface code, which avoids name mangling issues when linking against C source files or a C library.

Set CLinkage to true when creating an interface for a library defined by:

  • C header and library files.

  • C header and source files.

If CLinkage is false, then the function treats .h header files as C++ files. Use the default (CLinkage is false) when creating an interface from C++ files with C dependencies. In this case, the C file is specified by one of these arguments:

For examples showing how to use C files in clibgen.generateLibraryDefinition arguments, see "Files in Your Library" in Tips and search for CLinkage.

Data Types: logical

List of macro definitions to use while parsing header files, specified as empty, a scalar string, or a row vector of scalar strings. The macro name contains characters 1–9, a–z, A–Z, and '_' and cannot begin with a numeral.

Data Types: string

List of macro cancellations to use while parsing header files, specified as empty, a scalar string, or a row vector of scalar strings. The macro name contains characters 1–9, a–z, A–Z, and '_' and cannot begin with a numeral.

Data Types: string

Since R2022a

List of compiler flags, specified as a string array, character vector, or cell array of character vectors, to append to the compiler flags used to build the interface. The function passes the flags directly to the compiler without validation.

For more information, see Build C++ Library Interface and Review Contents.

Example: clibgen.generateLibraryDefinition("A.hpp","AdditionalCompilerFlags","-std=c++20")

Data Types: char | string | cell

Since R2022a

List of linker flags, specified as a string array, character vector, or cell array of character vector, to append to the linker flags used to build the interface. The function passes the flags directly to the linker without validation.

For more information, see Build C++ Library Interface and Review Contents.

Data Types: char | string | cell

Definition Configurations

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Shape specifier for object pointers, specified as a numeric or logical 1 (true) or 0 (false). If TreatObjectPointerAsScalar is true, then the function treats all object pointers in the library as scalars by specifying SHAPE as 1. Otherwise, the shape of the object pointer is unknown.

Introduced in R2019b.

Data Types: logical

Shape and MATLAB type specifier for const character pointers, specified as a numeric or logical 1 (true) or 0 (false). If TreatConstCharPointerAsCString is true, then the function treats all const character pointers in the library as null-terminated C strings by specifying MLTYPE as string and SHAPE as nullTerminated. Otherwise, MATLAB type and the shape of const character pointers are unknown. Supported pointer types are:

  • const char *

  • const wchar_t *

  • const char16_t *

  • const char32_t *

Data Types: logical

Option specifying how to return non-object C++ arrays, specified as a numeric or logical 1 (true) or 0 (false). If ReturnCArrays is true, then the function converts C++ arrays to the MATLAB clib array type (clib.array.*). If false, then the function converts C++ arrays to native MATLAB arrays.

Data Types: logical

Option to generate documentation from C++ files, specified as a numeric or logical 1 (true) or 0 (false). If GenerateDocumentationFromHeaderFiles is true, then the function generates documentation from comments in C++ files for display using the MATLAB doc command. If false, then the function ignores C++ comments and only generates documentation of MATLAB and C++ type mappings.

For more information, see Publish Help Text for MATLAB Interface to C++ Library.

Data Types: logical

Limitations

  • Saving LibraryDefinition object definelibName into a MAT-file is not supported.

  • Avoid non-ASCII characters in folder and filenames, as some locale settings do not support those characters. For information about locale, see Set Locale and Display Language.

Tips

  • To recreate a library definition file, call clibgen.generateLibraryDefinition with name-value argument OverwriteExistingDefinitionFiles set to true. When you use this option, the function deletes the files, including edits you might have made to the files.

  • For troubleshooting information, see Troubleshooting C++ Library Definition Issues.

  • Your library might contain combinations of C/C++ header files, source files, and compiled library files. This table shows how to set the arguments to clibgen.generateLibraryDefinition depending on what types of files define your library.

    Files in Your Library

    InterfaceGenerationFiles
    Argument

    		Name-Value Argument(s)

    Single CPP header file and import library file on Windows.

    • A.hpp

    • A.lib import library file in folder C:\Documents\MATLAB\

    Example: Header and C++ Compiled Library Files on Windows

    "A.hpp"

    Libraries="C:\Documents\MATLAB\A.lib"

    CPP header file and compiled object file on Linux.

    • A.hpp

    • A.so in folder ~/MATLAB/

    Example: Header and C++ Compiled Library Files on Linux

    "A.hpp"

    Libraries="~/MATLAB/A.so"

    CPP header file and dynamic compiled library file on macOS.

    • A.hpp

    • A.dylib in folder $home/Documents/MATLAB

    "A.hpp"

    Libraries="$home/Documents/MATLAB/A.dylib"

    Completely defined by CPP header and source files. No library files.

    • Header file A.hpp

    • Source file A.cpp

    Example: Header and C++ Source Files

    "A.hpp"

    SupportingSourceFiles="A.cpp"

    Multiple CPP header files, a source file, and a compiled library file. Create interface named A.

    • Header files A.hpp and B.hpp

    • Source file A.cpp

    • Compiled library file B.lib in C:\Documents\MATLAB\

    ["A.hpp","B.hpp"]

    InterfaceName="A"a

    Libraries="C:\Documents\MATLAB\B.lib"

    SupportingSourceFiles="A.cpp"

    CPP header-only library. The library is completely defined in a header file and does not have a compiled library file.

    • A.hpp

    Example: Header-Only HPP File

    "A.hpp"

    Not applicable

    Completely defined in a CPP source file and does not have a compiled library file.

    • A.cpp

    "A.cpp"

    Not applicable

    Completely defined by C header and source files. No library files.

    • A.h

    • A.c

    "A.h"

    SupportingSourceFiles="A.c"

    CLinkage=true

    Single C header file and import library file on Windows.

    • A.h

    • A.lib in C:\Documents\MATLAB\

    "A.h"

    Libraries="C:\Documents\MATLAB\A.lib"

    CLinkage=true

    The CPP source file depends on C header and source files.

    • Source file myCPP.cpp

    • Header and source files A.h and A.c in C:\Documents\MATLAB\

    		"myCPP.cpp"

    SupportingSourceFiles="C:\Documents\MATLAB\A.c"

    The C library depends on a CPP source file.

    • Header and source files A.h and A.c in C:\Documents\MATLAB\

    • Source file myCPP.cpp

    ["C:\Documents\MATLAB\A.h", "myCPP.cpp"]

    		InterfaceName="myCPP"

    SupportingSourceFiles="C:\Documents\MATLAB\A.c"

    CLinkage=true

    Library defined by CPP and C header files with corresponding library files in C:\Documents\MATLAB\.

    • myCPP.hpp

    • myCPP.lib

    • myC.h

    • myC.lib

    ["myCPP.hpp","myC.h"]

    		InterfaceName="myCPP"

    Libraries=["C:\Documents\MATLAB\myCPP.lib","C:\Documents\MATLAB\myC.lib"]

    CLinkage=true

    The C header file depends on a CPP header file.

    • A.h

    • B.hpp in C:\Documents\MATLAB\

    "A.h"

    IncludePath="C:\Documents\MATLAB\"

    a Because you have multiple header files, you must set the InterfaceName name-value argument. For example, if you set InterfaceName to "A", then when you call library function functionname from MATLAB, the syntax is clib.A.functionname.

Alternative Functionality

Live Task

Call the clibPublishInterfaceWorkflow function to use the Generate C++ Interface live task.

Version History

Introduced in R2019a

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See Also

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