# concurrencykit/ck

Concurrency primitives, safe memory reclamation mechanisms and non-blocking (including lock-free) data structures designed to aid in the research, design and implementation of high performance concurrent systems developed in C99+.

Repository: https://github.com/concurrencykit/ck
Canonical: https://ross.abutalabs.com/products/ck
Homepage: http://concurrencykit.org/
Language: C
License: NOASSERTION
License Family: other
Last push: 2026-08-10T20:03:51+00:00

## Health v2 (maintenance only)
Score: 66/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 97, release rhythm 8, longevity 100
- inputs: {"age_days": 4521, "days_push": 23, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2690, forks 334 (observed 2026-08-28T04:07:10.948678+00:00)

## What it is
Concurrency Kit (ck) is a C99 library providing concurrency primitives, safe memory reclamation mechanisms (epoch-based and hazard pointers), and non-blocking/lock-free data structures. It includes architecture-specific assembly optimizations for many platforms with compiler built-in fallbacks.

## Use cases
- implement lock-free queues in C
- safe memory reclamation for concurrent data structures
- atomic operations and CAS primitives across architectures
- build high-performance concurrent systems
- concurrent bitmap and pointer array structures
- research non-blocking algorithms

## When to choose
- writing performance-critical C/C++ concurrent code needing lock-free structures
- you need battle-tested safe memory reclamation (epoch or hazard pointers)
- targeting multiple architectures with specialized assembly support

## When to avoid
- you want a high-level threading API with locks and thread pools
- working in a managed language with garbage collection
- your project is not in C99+ or lacks a configure-based build

## Facets
- artifact type: library
- maturity: stable
- function: concurrency, developer-tools
- domain: performance, developer-tools, operating-systems
- platform: windows, bsd, cpp, c, cross-platform
- tags: lock-free, memory-reclamation, hazard-pointers, epoch-based-reclamation, atomic-operations, c99, high-performance, data-structures, algorithms, linux, macos

## Member repositories
- concurrencykit/ck (main) score 66

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:07:10.948678+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T02:16:34.625630+00:00, confidence not recorded.
  - readme: https://github.com/concurrencykit/ck (fetched 2026-08-28T04:07:10.948678+00:00, sha 7f8fb20fc31e)
  - homepage: http://concurrencykit.org/ (fetched 2026-08-29T09:59:37.303359+00:00, sha 956b7880c945)
- Data as of 2026-08-30T08:39:29.467469+00:00.