clang-uml is an automatic C++ to UML class, sequence, package and include diagram generator, driven by
YAML configuration files. The main idea behind the
project is to easily maintain up-to-date diagrams within a code-base or document
legacy code. The configuration file or files for clang-uml define the
types and contents of each generated diagram.
The diagrams can be generated in PlantUML and JSON formats.

clang-uml currently supports C++ up to version 17 with partial support for C++ 20.

Full documentation can be found at clang-uml.github.io.

To see what clang-uml can do, checkout the diagrams generated for unit
test cases here or examples in
clang-uml-examples repository.

Features

Main features supported so far include:

• Class diagram generation
  • Class properties and methods including access – example
  • Class inheritance – example
  • Other class relationships including associations, aggregations, dependencies and friendship – example
  • Template instantiation relationships – example
  • Template specialization and instantiation based on deduced context – example
  • Relationship inference from C++ containers and smart pointers – example
  • Diagram content filtering based on namespaces, elements and relationships – example
  • Optional package generation from namespaces – example
  • Optional package generation from subdirectories – example
  • Interactive links to online code to classes, methods and class fields in SVG diagrams – example
  • Support for plain C99/C11 code (struct and units relationships) – example
  • C++20 concept constraints – example
• Sequence diagram generation
  • Generation of sequence diagram from specific method or function – example
  • Generation of loop and conditional statements – example
  • Generation of switch statements – example
  • Generation of try/catch blocks – example
  • Handling of template code including constexpr conditionals – example
  • Handling of lambda expressions – example
  • Interactive links to online code to classes and call expressions – example
• Package diagram generation
  • Generation of package diagram based on C++ namespaces – example
  • Generation of package diagram based on subdirectories – example
  • Dependencies between packages based on symbols used in the code – example
  • Interactive links to online code to packages – example
• Include graph diagram generation
  • Show include graph for selected files – example

More comprehensive documentation can be at clang-uml.github.io.

Installation

Installation instructions for Linux, macos and Windows can be found
here.

Usage

Generating compile commands database

clang-uml requires an up-to-date
compile_commands.json
file, containing the list of commands used for compiling the source code.
Nowadays, this file can be generated rather easily using multiple methods:

• For CMake projects, simply invoke the cmake command
  as cmake -DCMAKE_EXPORT_COMPILE_COMMANDS=ON ...
• For Make projects checkout compiledb
  or Bear
• For Boost-based projects
  try commands_to_compilation_database
• For SCons, invoke compilation_db tool (requires SCons > 4.0.0)
• For Microsoft Visual Studio projects try Clang Power Tools

Invocation

By default, config-uml will assume that the configuration file .clang-uml
and compilation database compile_commands.json files are in the
current directory, so if they are in the top level directory of a project,
simply run:

The output path for diagrams, as well as alternative location of
compilation database can be specified in .clang-uml configuration file.

For other options checkout help:

Configuration file format and examples

Configuration files are written in YAML, and provide a list of diagrams
which should be generated by clang-uml. Basic example is as follows:

compilation_database_dir: .
output_directory: puml
diagrams:
  myproject_class:
    type: class
    glob:
      - src/*.cc
    using_namespace:
      - myproject
    include:
      namespaces:
        - myproject
    exclude:
      namespaces:
        - myproject::detail
    plantuml:
      after:
        - 'note left of {{ alias("MyProjectMain") }}: Main class of myproject library.'

See here for detailed configuration file reference guide.

Examples

To see what clang-uml can do, checkout the test cases documentation here.

In order to see diagrams for the clang-uml itself, based on its own config run
the following:

and checkout the SVG diagrams in docs/diagrams folder.

Class diagrams

Example

The following C++ code:

namespace clanguml {
namespace t30003 {

namespace ns1 {
namespace ns2_v1_0_0 {
class A {
};
}

namespace [[deprecated]] ns2_v0_9_0 {
class A {
};
}

namespace {
class Anon final {
};
}
}

namespace [[deprecated]] ns3 {

namespace ns1::ns2 {
class Anon : public t30003::ns1::ns2_v1_0_0::A {
};
}

class B : public ns1::ns2::Anon {
};
}
}
}

tests/t40001
├── include
│   ├── lib1
│   │   └── lib1.h
│   └── t40001_include1.h
└── src
    └── t40001.cc