.hDistinct files in the full Software Heritage archive (2026-06-04 export), dated by first appearance, following Desmazières, Di Cosmo, Lorentz (MSR 2025). Case-aggregated. citation.
Case variants in archive: .h (268.2M), .H (1.2M) — aggregated above.
This extension is attributed to C; C++; Objective-C as primary by 3 authoritative claims.
Disagree or have a correction? Open a labelling issue.
| Label | Annotator | Status | Evidence (excerpt) | |
|---|---|---|---|---|
| pl/cpp — ref | @acherm | new | Objective C is using .h as well as C and C++. Perhaps other C-like languages are also using .h | discuss |
| pl/objective-c — ref | @acherm | new | Objective C is using .h as well as C and C++. Perhaps other C-like languages are also using .h | discuss |
| pl/c — ref | @acherm | new | Objective C is using .h as well as C and C++. Perhaps other C-like languages are also using .h | discuss |
.h among their extensions. Strength reflects whether the upstream source treated it as their primary extension.| Language | Source | Strength |
|---|---|---|
| C | wikidata | primary |
| C++ | wikidata | primary |
| Objective-C | wikidata | primary |
| C | linguist | secondary |
| C | pygments | secondary |
| C (programming language) | pygments | secondary |
| C++ | linguist | secondary |
| C++ | pygments | secondary |
| cpp | pygments | secondary |
| Objective-C | linguist | secondary |
| Objective-C | pygments | secondary |
| C | manual_review:acherm | proposed |
| C++ | manual_review:acherm | proposed |
| Objective-C | manual_review:acherm | proposed |
.h on Wikidata
(property P1195) or in the Wikipedia infobox.
Source: data/derived/external_extension_index.csv.
Click Use as new PL on any row to open the
Add-PL form pre-filled with that entry's name, Wikipedia/Wikidata
URL, and this extension — one submission creates the PL + claim.
| Format | Class (Wikidata P31) | Suggested label | MIME | Notes | Action |
|---|---|---|---|---|---|
| header file Q877809 file containing source code with declarations to be textually substituted by users | — | — | — | Use as new PL ↗ | |
| C header file Q29642901 file format | file format | — | — | — | Use as new PL ↗ |
| C++ header Q13039854 file format | file format | — | — | — | Use as new PL ↗ |
.h file actually is.| Rule | Predicts | Kind | Predicates (truncated) | Measured on SWH |
|---|---|---|---|---|
h/linguist/.h/0 | Objective-C | predicates | [{"kind": "any", "regexes": ["^\\s*(@(interface|class|protocol|property|end|synchronised|selector|implementation)\\b|#import\\s+.+\\.h[\">])"]}] | |
h/linguist/.h/1 | C++ | predicates | [{"kind": "any", "regexes": ["^\\s*#\\s*include <(cstdint|string|vector|map|list|array|bitset|queue|stack|forward_list|unordered_map|unordered_set|(i|o|io)stream)>", "^\\s*template\\s*<", "^[ \\t]*(tr | |
h/linguist/.h/2 | C | default | [] |