Hornet C/C++

Hornet C/C++ is a C/C++ language extension for VS Code with four parsing modes, project indexing and interactive function call graphs.

Demo

Explore call relationships and navigate to the code. The demo shows the call graph, animated connection tracing, four parsing modes, and shortcuts for CPU usage, logs and index maintenance. The graph also supports expanding and collapsing branches.

Open the demo · Download the latest release

This repository distributes extension installers and user documentation. This release channel has its own version sequence, starting at 0.0.1.

Download and install

Open the latest release and download the appropriate .vsix file from Assets.

In VS Code, open Extensions, choose … → Install from VSIX…, select the installer, then run Developer: Reload Window.

You can also install from the command line:

code --install-extension ./hornet-cpp-0.0.2-win32-x64.vsix --force

The Marketplace extension ID is codehubcloud.hornet-cpp. VS Code 1.85 or later is required. Earlier GitHub 0.0.1/0.0.2 packages used hornet.hornet-cpp: uninstall that extension, install the Marketplace edition, and reload VS Code. A different publisher creates a different extension identity, so this migration requires a manual installation once. Do not keep both editions enabled.

For Remote SSH, WSL or Dev Containers, install the extension on the workspace host and choose an installer for that host's operating system. Browser-only VS Code cannot run the local processes required by this extension.

Check for updates

For the Marketplace edition, VS Code's Auto Update uses the extension marketplace. The built-in Check for Updates command described below checks GitHub Releases separately. The already-published GitHub 0.0.2 assets retain their original hornet publisher; they are not the Marketplace migration installer.

Run Hornet C/C++: Check for Updates, or select Check for Updates in the Hornet status menu. Hornet checks the public release repository and selects the VSIX for the workspace host, including SSH, WSL and containers. Choose Download and Install to verify its SHA-256 checksum and install through VS Code, then reload the window. Open Release opens the release page instead.

Startup checks run at most once per day and notify once per available version. Set hornet-cpp.updates.checkOnStartup to false for manual checks only. Checks and downloads respect the VS Code HTTP proxy and HTTPS_PROXY / HTTP_PROXY. Background failures appear in Open Logs; manual failures also offer the release page.

Version correction: This release is 0.0.2, following 0.0.1. The incorrectly numbered 0.0.11 release is withdrawn. If you installed it, manually install the 0.0.2 VSIX and reload; that older package does not contain the update checker.

User guide and walkthrough

Run Hornet C/C++: Get Started for the built-in five-step walkthrough, or Hornet C/C++: Open User Guide for the offline manual. Both are also available from the Hornet status menu. The walkthrough follows the VS Code display language and remembers progress; English and Chinese manuals are bundled. VS Code handles the walkthrough's initial display on installation.

Open your first project

1. Open and trust a C/C++ project folder.
2. The default Hybrid mode discovers compilation databases automatically. Files with compile commands use clangd; without a database, the Tag index provides basic browsing. Automatic clangd download and verification are available on Windows x64, glibc Linux x64, and macOS x64/ARM64. On other targets, install clangd or choose Tag / Flyweight.
3. Hornet builds the project index. A spinning status icon and a percentage with file counts show progress; hover for details. When indexing completes, the status changes to Hornet C/C++: idle.
4. Right-click a function and choose Hornet Show Graph.

Platform-specific installers do not include a native clangd or compiler. Cross-compilation projects still need the actual toolchain, header paths and preprocessor definitions.

Features

• Completion, hover information, signature help, definition/declaration navigation and references.
• Rename, code actions, formatting, semantic highlighting, inlay hints, outlines and symbol search.
• Call hierarchy, type hierarchy and interactive function call graphs.
• Compilation database import, merge, validation, discovery and project index refresh.
• Separate configuration and language services for each workspace folder.

Available semantic features depend on the selected server and the completeness of the project's compile commands. The bundled formatter is also available in Tag and Flyweight modes.

Function call graph

Right-click a C/C++ function and run Hornet Show Graph to open the Hornet Graph panel.

• Use the plus/minus buttons on either side of a function to expand or collapse relationships. The selected function keeps its screen position and zoom level while new nodes are arranged around it.
• Use the toolbar to expand or collapse branches together. Expansion respects the configured depth and the graph's node limit.
• Hover over or click a connection to highlight its calling direction.
• Click the background or press Esc to clear the selected connection.
• Drag the background to pan, scroll or use the toolbar to zoom, and double-click a function to navigate to its code.
• Use the center action to continue exploring from a different function.

Each graph loads up to 250 functions. For larger call chains, change the center to explore another section. Branch groups receive their own space, sequential call chains remain horizontally aligned, and connection arrows attach to function ports.

Compilation settings and indexing

Hornet stores processed compile commands in .vscode/hornet/compile-db/compile_commands.json. Run Hornet C/C++: Import Compilation Database to import an existing database, or use a configured CMake build directory.

Without complete compile commands, macros, conditional compilation, header resolution and call relationships may be incomplete. Hybrid limits rename, code actions and diagnostics for files without compile commands. Compiler mode uses clangd's capabilities.

Run Hornet Build Index, or click the indexing status item, to refresh the index. Indexing does not compile or link your program.

Example settings:

{
  "hornet-cpp.languageProvider": "Hybrid",
  "hornet-cpp.clangd.path": "clangd",
  "hornet-cpp.cpuUsage": "Medium",
  "hornet-cpp.clangd.ignoreDiagnostics": "not_indexed",
  "hornet-cpp.clangd.enableInlayHints": true,
  "hornet-cpp.syntaxColor.enable": true
}

Open extension settings with Hornet C/C++ → gear → Extension Settings, or search for @ext:codehubcloud.hornet-cpp. Setting descriptions and option labels follow the VS Code display language. JSON configuration keys and saved values remain unchanged.

To use your own formatting configuration, set hornet-cpp.clangd.formatFilePath to an absolute path or a workspace-relative path such as ${workspaceFolder}/config/.clang-format. An explicit file takes priority over project configuration. If no file is found and clangd.forceFormatStyle is enabled, the bundled Hornet fallback uses LLVM style with four-space indentation and a 120-column limit.

Parsing modes

Click the mode in the status bar or run Hornet C/C++: Switch Parsing Mode.

Tag / Flyweight provide symbol search, outlines, completion, definition/declaration navigation, syntax references and call graphs. They do not run preprocessing, type checking or refactoring; symbols with identical names may produce multiple candidates. Use Compiler, or supply compile commands for Hybrid, when precise semantic results are needed. Flyweight performance depends on the project and editing patterns.

The built-in syntax index can persist a JSON cache and refresh it from project files. Source and header discovery includes uppercase file extensions and is independent of .gitignore, files.exclude and search.exclude. Hornet's global and mode-specific exclusions determine what is indexed; Tag and Flyweight exclude build/output directories by default. Read or parse failures are recorded in the logs. Parser and formatter WebAssembly assets are bundled in the VSIX.

Custom native server executables must support the expected protocol. The built-in cache, symbol search and Hornet formatting fallback are this project's implementations; related settings describe differences from the original custom servers.

Status and maintenance

Hover over Hornet C/C++: idle to see activation state, installed version, mode and CPU usage. Click the status item to open the maintenance menu.

• Open Extension Logs / Open Clangd Logs / Open Hornet-DB Logs open extension, compiler and syntax-index logs.
• Open Settings opens Hornet settings. The mode and CPU controls offer direct changes. CPU usage defaults to Maximum; High, Medium and Low are also available.
• Update Index refreshes the current index. Rebuild Index restarts parsing, clears the workspace's standard clangd index cache and scans the project again.
• Reload window reloads VS Code.
• Clear Errors clears current Hornet diagnostics. Later analysis may report them again.
• FAQ opens troubleshooting information.

CPU settings control clangd's thread budget and the background parser's duty cycle; they are approximate targets rather than operating-system resource limits. Hornet-DB is the log name for the lightweight syntax index.

FAQ

clangd download failed: Run Hornet C/C++: Auto Setup clangd to retry, or Hornet C/C++: Configure clangd to select an installed executable. Downloads support VS Code's HTTP proxy and the HTTPS_PROXY / HTTP_PROXY environment variables. Hybrid can continue with its syntax index; Flyweight is another available mode.

Index or call relationships are incomplete: Check the compilation database, toolchain paths, include paths and preprocessor definitions. Status details distinguish project-file scanning from clangd compilation-database tasks. Check the logs and Hornet exclusion settings for failures or excluded files.

Duplicate completion or diagnostics: Check whether another enabled C/C++ extension is providing the same language features.

Inspect logs: Run Hornet C/C++: Open Logs, then check the extension version and clangd startup messages.

Feedback

Report problems in Issues, including the operating system, CPU architecture, VS Code/extension/clangd versions and reproduction steps. Review logs before sharing them because they may contain local project paths.

Third-party notices

The installer includes LICENSE.txt and ThirdPartyNotices.txt. clangd is installed separately under its own license. Hornet C/C++ is an independent tool, not Microsoft's official C/C++ extension.

code --install-extension ./hornet-cpp-0.0.2-win32-x64.vsix --force

{
  "hornet-cpp.languageProvider": "Hybrid",
  "hornet-cpp.clangd.path": "clangd",
  "hornet-cpp.cpuUsage": "Medium",
  "hornet-cpp.clangd.ignoreDiagnostics": "not_indexed",
  "hornet-cpp.clangd.enableInlayHints": true,
  "hornet-cpp.syntaxColor.enable": true
}