clibgen.generateLibraryDefinition

R2026b

(Not recommended) Create definition file for C/C++ library

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The recommended way to generate MATLAB® definitions for a C/C++ library is to create a clibgen.api.InterfaceConfiguration object. For more information on updating your code, see Version History.

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/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.

You need a C/C++ compiler that MATLAB supports. You must build the interface library using the same compiler that was used to build the C/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/C++ compiler to build the interface library. For information about your C/C++ compilers, type:

mex -setup cpp
mex -setup c

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.

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.

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®.

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).

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")

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.

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 arguments.

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. 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.

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 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: SupportingSourceFiles="sample.cpp"

Folders for included header files, specified as a string array, character vector, or cell array of character vectors. If the main header file contains #include statements for header files in different folders, then use the IncludePath argument to specify these paths. Each value in IncludePath must be the full pathname to folders to include during compilation of the header files. If your library does not need an include path, set IncludePath to an empty string.

Example: IncludePath=fullfile("toolbox/acme/include")

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.

Use the InterfaceName to call the library from MATLAB.

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.

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.

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.

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 your interface, see "Files in Your Library" in Tips and search for CLinkage.

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.

Macro cancellations for parsing header files, specified as a string row vector. Each macro name can contain the characters 1–9, a–z, A–Z, and "_" and cannot begin with a numeral.

Example: UndefinedMacros="D3"

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/C++ Library Interface and Review Contents.

Example: AdditionalCompilerFlags="-std=c++20"

Since R2022a

List of linker flags, specified as a string vector, 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/C++ Library Interface and Review Contents.

Definition Configurations

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Treat object pointer as scalar value, specified as a numeric or logical 1 (true) or 0 (false). If TreatObjectPointerAsScalar is true, then the interface treats all object pointers in the library as scalar values by specifying SHAPE as 1. Otherwise, the shape of object pointers is unknown.

Treat const character pointer as C string, specified as a numeric or logical 1 (true) or 0 (false). If TreatConstCharPointerAsCString is true, then the interface treats all const character pointers in the library as null-terminated C strings by specifying MLTYPE as string and SHAPE as nullTerminated. Otherwise, the 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 *

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.

Generate documentation from C++ files, specified as a numeric or logical 1 (true) or 0 (false). By default, GenerateDocumentationFromHeaderFiles generates documentation from comments in C++ files. The MATLAB doc command displays this documentation in the Command Window. If you set this property to false, then the interface ignores C++ comments and generates documentation only for MATLAB and C++ type mappings.

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

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.

Version History

Introduced in R2019a

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See Also

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Functions

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