Features
Contents
Here is what clangd can do for you. Screenshots below show VSCode; the available features and UI depend on the editor.
Errors and warnings
clangd runs the clang compiler on your code as you type, and shows errors and warnings in-place. Some errors are suppressed: diagnostics that require expanding templates in headers are disabled for performance reasons.
:raw-html:`<details><summary markdown="span">Screenshot</summary>`
Fixes in errors and warnings
The compiler can suggest fixes for many common problems automatically, and clangd can update the code for you.
:raw-html:`<details><summary markdown="span">Animated demo</summary>`
(New in v9) If a missing symbol was seen in a file you've edited recently, clangd will suggest inserting it.
clang-tidy checks
(New in v9) clangd embeds clang-tidy which provides extra hints about code problems: bug-prone patterns, performance traps, and style issues.
:raw-html:`<details><summary markdown="span">Animated demo</summary>`
clangd respects your project's .clang-tidy file which controls the checks
to run. Not all checks work within clangd. You must pass the -clang-tidy
flag to enable this feature.
Code completion
You'll see suggestions as you type based on what methods, variables, etc are available in this context.
:raw-html:`<details><summary markdown="span">Screenshot</summary>`
Abbreviating words may help you find the right result faster. If you type in
camelCase but the function you're looking for is snake_case, that's OK.
Insertion of namespace qualifiers and includes
(New in v8)
clangd will sometimes suggest results from other files and namespaces. In this
case the correct qualifier and #include directive will be inserted.
:raw-html:`<details><summary markdown="span">Animated demo</summary>`
Signature help
Some editors will show you the parameters of the function you're calling, as you fill them in.
:raw-html:`<details><summary markdown="span">Animated demo</summary>`
Cross-references
The following features let you navigate your codebase.
If there is no project-wide index, cross-references work across the files you have opened.
(New in v9) clangd will also automatically index your whole project.
Find definition/declaration
Jump to the definition or declaration of a symbol under the cursor.
:raw-html:`<details><summary markdown="span">Animated demo</summary>`
(New in v9) Some editors only expose "find definition"; use "find definition" on the definition to jump to the declaration.
"Find definition" also works on #include lines, to jump to the included
file.
Find references
Show all references to a symbol under the cursor.
:raw-html:`<details><summary markdown="span">Animated demo</summary>`
Some editors will automatically highlight local references to the selected symbol as you move around a file.
Navigation
clangd informs the editor of the code structure in the current file. Some editors use this to present an outline view:
:raw-html:`<details><summary markdown="span">Screenshot</summary>`
In VSCode, the outline is also presented as breadcrumbs that allow jumping to a symbol within the current file. Searching for symbols within the scope of the whole project is also possible.
:raw-html:`<details><summary markdown="span">Animated demo</summary>`
Formatting
clangd embeds clang-format, which can reformat your code: fixing indentation, breaking lines, and reflowing comments.
:raw-html:`<details><summary markdown="span">Animated demo</summary>`
clangd respects your project's .clang-format file which controls styling
options.
Format-as-you-type is experimental and doesn't work well yet.
Complete list of features
Here is a list of features that could be useful for editors, together with the implementation status in clangd, and specification in the Language Server Protocol.
It is not clear whether or not some of the features mentioned below should be a part of the Language Server Protocol; those features might be eventually developed outside clangd or become clangd extensions to LSP.
| C/C++ Editor feature | LSP | Clangd |
|---|---|---|
| Formatting | Yes | Yes |
| Completion | Yes | Yes |
| Diagnostics | Yes | Yes |
| Fix-its | Yes | Yes |
| Go to Definition | Yes | Yes |
| Signature Help | Yes | Yes |
| Document Highlights | Yes | Yes |
| Rename | Yes | Yes |
| Source hover | Yes | Yes |
| Find References | Yes | Yes |
| Document Symbols | Yes | Yes |
| Workspace Symbols | Yes | Yes |
| Code Lens | Yes | No |
| Code folding | Yes | No |
| Extract Local Variable | Yes | No |
| Extract Function/Method | Yes | No |
| Quick Assist | Yes | No |
| Hide Method | Yes | No |
| Implement Method | Yes | No |
| Gen. Getters/Setters | Yes | No |
| Syntax and Semantic Coloring | Proposed [1] | Yes |
| Call hierarchy | Proposed [2] | No |
| Type hierarchy | Proposed [3] | Yes |
| Organize Includes | Yes | No |
| [1] | https://github.com/microsoft/language-server-protocol/issues/18 |
| [2] | https://github.com/microsoft/language-server-protocol/issues/468 |
| [3] | https://github.com/microsoft/language-server-protocol/issues/136 |