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`.hh`

4 claimants 1 primary 3 secondary unambiguous primary

SWH popularity

Distinct 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.

4.7M

total files

1.2M

first seen 2021–2025 (25.8%)

2017

median year (half its files since)

Case variants in archive: .hh (4.7M), .HH (1.3K), .Hh (15) — aggregated above.

Attribution status

This extension is attributed to C++ as primary by 1 authoritative claim.

Authoritative sources: △ Linguist · secondary △ Pygments · secondary ✓ Wikidata · Q2407 ✗ Wikipedia · no claim

Disagree or have a correction? Open a labelling issue.

Claimants (6)

Languages that list .hh among their extensions. Strength reflects whether the upstream source treated it as their primary extension.

Language	Source	Strength
C++	wikidata	primary
C++	linguist	secondary
C++	pygments	secondary
cpp	pygments	secondary
Hack	linguist	secondary
Objective-C++	pygments	secondary

Wikidata says… (2)

File formats, image formats, audio codecs and other non-PL entities that claim .hh 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.

Right entry isn't listed? Add manually ↗

Format	Class (Wikidata `P31`)	Suggested label	MIME	Notes	Action
C++ header Q13039854 file format	file format	—	`—`	—	Use as new PL ↗
HammerHead Rhythm Station pattern Q105857161 file format	file format	—	`application/octet-stream`	—	Use as new PL ↗

Disambiguation rules (1)

Linguist heuristics that decide, by content, which language a .hh file actually is.

Rule	Predicts	Kind	Predicates (truncated)	Measured on SWH
`h/linguist/.hh/0`	Hack	predicates	`[{"kind": "any", "regexes": ["<\\?hh"]}]`

SWH-mined examples (3)

Real archived programs with this extension, byte-verified against the SWH archive, grouped by predicted language and by how the prediction was made. Useful for deciding what this extension actually is when the attribution is uncertain.

unclassified (3) — 3 via fallback

BKE_node_runtime.hh · 25636 B · seen 510× in SWH

predicted: unclassified via fallback

swh:1:cnt:afebe5c63ec2e72fd4fbd9f8efc14026ae3afa3d;origin=https://github.com/asd158/blender3.5.1;anchor=swh:1:rev:d25f4f71c312a5de61486349ae02551988266aed;path=/src/source/blender/blenkernel/BKE_node_runtime.hh

Open in SWH · Raw bytes

BKE_node.hh · 12259 B · seen 464× in SWH

predicted: unclassified via fallback

swh:1:cnt:d6c8353da42015c26f04840a392fdad083dd3905;origin=https://github.com/dshawshank/Blender-android_arm64;anchor=swh:1:rev:c8b5b17d40c4e969fada2e89873edaf0dda5cd30;path=/source/blender/blenkernel/BKE_node.hh

Open in SWH · Raw bytes

GHOST_SystemSDL.hh · 2527 B · seen 183× in SWH

predicted: unclassified via fallback

swh:1:cnt:67e093f3ddd12d5059fc29462e5b64848d601fc1;origin=https://github.com/dshawshank/Blender-android_arm64;anchor=swh:1:rev:b626f1fd18e98b18a8ea1ac90fbf659cd23ee361;path=/intern/ghost/intern/GHOST_SystemSDL.hh

Open in SWH · Raw bytes