community/developer-guide/cpp-diagnostic-code.md

---
title: C++ Static Code Analysis
language: en
description: "Apache Doris C++ static code analysis: Clang-Tidy and Clangd configuration (including VSCode integration)."
keywords:
    - Apache Doris
    - C++ static analysis
    - Clang-Tidy
    - Clangd
    - VSCode
    - LDB toolchain
    - compile_commands.json
---

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# C++ Static Code Analysis

<!-- Knowledge type: Code conventions -->
<!-- Applicable scenarios: BE development / Code quality checks -->

Apache Doris supports static analysis of C++ code with [Clangd](https://clangd.llvm.org/) and [Clang-Tidy](https://clang.llvm.org/extra/clang-tidy/). Both are bundled in the [LDB-toolchain](/community/source-install/compilation-with-ldb-toolchain), and you can also install or build them yourself.

## Tool Comparison

| Tool | Purpose | Configuration file |
|------|---------|--------------------|
| Clangd | Provides IDE capabilities such as code navigation, completion, and hover hints | Passed in via `clangd.arguments` |
| Clang-Tidy | Static analysis and code quality checks (can be invoked by Clangd) | `.clang-tidy` in the Doris root directory |

Compared with `vscode-cpptools`, Clangd offers more accurate code navigation and integrates the diagnostics and quick-fix features of Clang-Tidy.

## Clang-Tidy Configuration

Clang-Tidy check rules are centralized in the `.clang-tidy` file in the Doris root directory. You can enable or disable specific checks by editing this file.

## Configuring Clangd in VSCode

<!-- Knowledge type: Tool usage -->

### Steps

1. Install the `clangd` plugin.
2. Before use, compile `be(RELEASE)` and `be-ut(ASAN)` once to generate the corresponding `compile_commands.json` files.
3. Edit `settings.json` or change the plugin configuration directly in Preferences.

### Configuration Example

```json
{
    "clangd.path": "ldb_toolchain/bin/clangd",
    "clangd.arguments": [
        "--background-index",
        "--clang-tidy",
        "--compile-commands-dir=doris/be/build_Release/",
        "--completion-style=detailed",
        "-j=5",
        "--all-scopes-completion",
        "--pch-storage=memory",
        "--pretty",
        "--query-driver=ldb_toolchain/bin/*"
    ],
    "clangd.trace": "output/clangd-server.log"
}
```

### Key Parameters

| Parameter | Description |
|-----------|-------------|
| `clangd.path` | Path to the Clangd executable |
| `--background-index` | Indexes the entire project in the background to speed up symbol lookup |
| `--clang-tidy` | Enables Clang-Tidy static checks |
| `--compile-commands-dir` | Specifies the directory containing `compile_commands.json` |
| `--completion-style=detailed` | Shows detailed information during completion |
| `-j=5` | Number of parallel jobs Clangd uses to analyze files |
| `--query-driver` | Path to the compiler, used to resolve system header files |

## FAQ

**Q: How do I troubleshoot `clangd` when it reports a missing header file or symbol?**

Confirm that BE has been compiled at least once to generate `compile_commands.json`, and that `--compile-commands-dir` points to the correct directory.