package lwt

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Promises and event-driven I/O

Install 

dune-project
 Dependency

github.com Edit opam file Versions (32)

Authors

  1. J
    Jérôme Vouillon
  2. J
    Jérémie Dimino

Maintainers

  1. R
    Raphaël Proust <code@bnwr.net>
  2. Anton Bachin

Sources

6.1.2.tar.gz
md5=00bc7eb2772a28530f7365a7040f0c4f
sha512=a4737a2fc44aaeedca46ec6134c07013d5cf44039a988a6e79a40715a53e43601d4c91bbf11a8e89540528d912b8fa487e3068465c136c1156a872258eb3443b

Description

A promise is a value that may become determined in the future.

Lwt provides typed, composable promises. Promises that are resolved by I/O are resolved by Lwt in parallel.

Meanwhile, OCaml code, including code creating and waiting on promises, runs in a single thread by default. This reduces the need for locks or other synchronization primitives. Code can be run in parallel on an opt-in basis.

Published: 29 Apr 2026

Dependencies (5)

  1. ocplib-endian
  2. dune-configurator
  3. cppo build & >= "1.1"
  4. ocaml >= "4.14"
  5. dune >= "3.18"

Dev Dependencies (2)

  1. odoc with-doc & >= "2.3"
  2. ocamlfind dev & >= "1.7.3-1"

  1. 0install >= "2.15.1"
  2. aches-lwt
  3. activitypub
  4. albatross
  5. alcotest-lwt
  6. alcotest-mirage
  7. ambient-context-lwt
  8. amqp-client >= "1.1.0"
  9. amqp-client-lwt
  10. angstrom-lwt-unix >= "0.11.0"
  11. anthill
  12. anycache-lwt
  13. archi-lwt
  14. arp
  15. awa-mirage
  16. aws-lwt
  17. aws-s3-lwt >= "4.8.1"
  18. awsm-lwt
  19. azure-cosmos-db < "0.4.0"
  20. azure-cosmos-db-lwt
  21. balancer
  22. bastet_lwt
  23. bimage-lwt
  24. bistro
  25. bizowie-api
  26. brisk-reconciler
  27. builder
  28. builder-web
  29. bun >= "0.3.3"
  30. cachet-lwt
  31. calculon
  32. caldav
  33. camltc
  34. canary
  35. capnp-rpc-lwt < "2.0"
  36. capnp-rpc-unix < "2.1"
  37. caqti-lwt < "2.3.0"
  38. caqti-mirage
  39. carton < "1.0.0"
  40. carton-git
  41. carton-lwt
  42. catala-format >= "0.2.0"
  43. cf-lwt
  44. chamelon
  45. chamelon-unix
  46. chamo
  47. charrua-client
  48. charrua-unix
  49. chess_com_api
  50. ciao_lwt
  51. clz
  52. cmdtui-lambda-term
  53. coap
  54. coap-server-lwt
  55. cohttp-curl-lwt
  56. cohttp-lwt
  57. cohttp-lwt-jsoo
  58. cohttp-lwt-unix
  59. cohttp-mirage
  60. cohttp-server-lwt-unix
  61. comby
  62. comby-semantic
  63. conan-lwt
  64. conduit-lwt
  65. conduit-lwt-unix
  66. cowabloga
  67. crunch
  68. cstruct-lwt
  69. csv-lwt
  70. ctypes >= "0.15.0" & < "0.21.1"
  71. ctypes-foreign >= "0.21.1"
  72. curl_lwt
  73. current
  74. current-albatross-deployer
  75. current_docker
  76. current_examples
  77. current_git
  78. current_github
  79. current_gitlab
  80. current_ocluster
  81. current_rpc
  82. current_slack
  83. current_web
  84. dap
  85. data-encoding < "0.1.1"
  86. devkit >= "1.2"
  87. distributed-lwt
  88. dkim-bin < "0.8.0"
  89. dkim-lwt-unix
  90. dkim-mirage
  91. dlm
  92. dmarc
  93. dns-certify
  94. dns-cli
  95. dns-client < "7.0.3"
  96. dns-client-lwt
  97. dns-client-mirage
  98. dns-forward
  99. dns-forward-lwt-unix
  100. dns-lwt
  101. dns-mirage
  102. dns-resolver
  103. dns-server
  104. dns-stub
  105. dnsrobot
  106. dnssd
  107. docker_hub
  108. docteur >= "0.0.2"
  109. docteur-solo5
  110. docteur-unix >= "0.0.5"
  111. doi2bib
  112. dream
  113. dream-httpaf
  114. dream-pure
  115. dream-serve < "1.0.1"
  116. dropbox
  117. dune >= "3.17.2"
  118. dune-rpc-lwt
  119. earlybird
  120. elasticsearch-cli
  121. emoji = "2.0.0"
  122. equinoxe
  123. ethernet
  124. ez_api >= "1.2.0"
  125. ezcurl-lwt
  126. ezjs_min < "0.2"
  127. ezjsonm-lwt
  128. ezresto
  129. faraday-lwt
  130. faraday-lwt-unix
  131. fat-filesystem
  132. fiber-lwt
  133. fsevents-lwt
  134. fswatch_lwt
  135. gdbprofiler
  136. git
  137. git-cohttp
  138. git-cohttp-unix
  139. git-kv >= "0.2.0"
  140. git-mirage
  141. git-paf
  142. git-unix >= "3.2.0"
  143. github
  144. github-hooks
  145. github-unix >= "4.4.0"
  146. gitlab-unix
  147. gitlab_pipeline_notifier
  148. gluten-lwt
  149. gluten-lwt-unix < "0.4.0"
  150. gluten-mirage < "0.4.0"
  151. graphql-lwt
  152. gremlin
  153. grpc-lwt
  154. guardian
  155. gufo
  156. h1
  157. h1-lwt-unix
  158. h2-lwt
  159. h2-lwt-unix < "0.10.0"
  160. h2-mirage
  161. happy-eyeballs-lwt
  162. happy-eyeballs-mirage
  163. hidapi-lwt
  164. hiredis >= "0.6"
  165. hl_yaml
  166. hockmd
  167. http-lwt-client
  168. http-mirage-client
  169. http-multipart-formdata >= "2.0.0" & < "3.0.0"
  170. httpaf-lwt-unix
  171. httpun-lwt
  172. httpun-mirage
  173. httpun-ws-lwt
  174. hvsock
  175. i3ipc
  176. influxdb-lwt
  177. inotify >= "2.4"
  178. inquire < "0.3.0"
  179. interface-prime-lwt
  180. ip2location
  181. ip2locationio
  182. ip2whois
  183. ipv6-multicast-lwt
  184. irc-client-lwt
  185. irc-client-lwt-ssl
  186. irc-client-tls
  187. irmin
  188. irmin-bench
  189. irmin-chunk
  190. irmin-cli
  191. irmin-client
  192. irmin-containers
  193. irmin-fs
  194. irmin-git
  195. irmin-graphql
  196. irmin-http
  197. irmin-indexeddb
  198. irmin-layers
  199. irmin-mirage-git
  200. irmin-mirage-graphql
  201. irmin-pack
  202. irmin-server
  203. irmin-test
  204. irmin-unix
  205. irmin-watcher
  206. joolog
  207. jose < "0.9.0"
  208. js_of_ocaml-lwt
  209. jsoo_broadcastchannel
  210. jsoo_storage
  211. jupyter
  212. jupyter-kernel
  213. kafka < "0.5"
  214. kafka_lwt
  215. kappa-library
  216. ke >= "0.5"
  217. kinetic-client
  218. kubecaml
  219. lambda-runtime
  220. lambda-term >= "3.3.3"
  221. lambda_streams_lwt
  222. launchd
  223. ldp
  224. learn-ocaml
  225. learn-ocaml-client
  226. ledgerwallet >= "0.4.0"
  227. letsencrypt < "2.0.0"
  228. letsencrypt-app
  229. letsencrypt-dns < "2.0.0"
  230. letters
  231. lichess_api
  232. links
  233. llama
  234. lru_cache
  235. lwt-canceler
  236. lwt-dllist
  237. lwt-exit
  238. lwt-parallel
  239. lwt-pipe
  240. lwt-pipeline
  241. lwt-watcher
  242. lwt_camlp4
  243. lwt_direct >= "6.0.0"
  244. lwt_domain != "0.2.0"
  245. lwt_eio >= "0.6"
  246. lwt_ppx >= "6.0.0"
  247. lwt_react
  248. lwt_retry
  249. lwt_ssl
  250. mariadb >= "1.2.0"
  251. markdown_monolith
  252. markup = "0.7.6"
  253. markup-lwt
  254. mdx
  255. mechaml
  256. mehari-lwt-unix
  257. mehari-mirage
  258. memtrace-mirage
  259. metrics-influx
  260. metrics-lwt
  261. metrics-unix
  262. mimic
  263. mindstorm-lwt
  264. mirage < "4.0.0"
  265. mirage-block >= "2.0.1"
  266. mirage-block-ccm
  267. mirage-block-combinators
  268. mirage-block-lwt
  269. mirage-block-partition
  270. mirage-block-ramdisk
  271. mirage-block-solo5
  272. mirage-block-unikraft
  273. mirage-block-unix >= "2.14.2"
  274. mirage-block-xen
  275. mirage-channel >= "4.0.1"
  276. mirage-channel-lwt
  277. mirage-clock-lwt
  278. mirage-clock-unix < "4.2.0"
  279. mirage-console-lwt
  280. mirage-crypto-rng < "0.11.3"
  281. mirage-crypto-rng-lwt
  282. mirage-crypto-rng-mirage
  283. mirage-device >= "2.0.0"
  284. mirage-flow >= "3.0.0"
  285. mirage-flow-combinators
  286. mirage-flow-lwt
  287. mirage-flow-unix
  288. mirage-fs >= "4.0.0"
  289. mirage-fs-lwt
  290. mirage-kv >= "3.0.1"
  291. mirage-kv-lwt
  292. mirage-kv-unix
  293. mirage-net >= "4.0.0"
  294. mirage-net-lwt
  295. mirage-net-macosx
  296. mirage-net-solo5
  297. mirage-net-unikraft
  298. mirage-net-unix
  299. mirage-net-xen
  300. mirage-profile
  301. mirage-protocols >= "7.0.0"
  302. mirage-protocols-lwt
  303. mirage-qubes
  304. mirage-qubes-ipv4
  305. mirage-runtime
  306. mirage-sleep
  307. mirage-solo5
  308. mirage-stack = "3.0.0"
  309. mirage-stack-lwt
  310. mirage-time >= "3.0.0"
  311. mirage-time-lwt
  312. mirage-time-unix
  313. mirage-types-lwt
  314. mirage-unikraft
  315. mirage-unix
  316. mirage-vnetif
  317. mirage-xen
  318. monorobot
  319. mqtt
  320. mrmime >= "0.5.0"
  321. multipart-form-data
  322. multipart_form >= "0.2.0" & < "0.4.0"
  323. multipart_form-cohttp-lwt < "0.6.0"
  324. multipart_form-lwt
  325. naboris
  326. nbd >= "4.0.3"
  327. nbd-tool
  328. nbd-unix
  329. neo4j_bolt
  330. nottui-lwt
  331. notty-community
  332. nproc
  333. nsq
  334. obuilder
  335. obus >= "1.2.1"
  336. ocaml-ai-sdk
  337. ocluster
  338. ocluster-api
  339. ocluster-worker
  340. ocplib-resto
  341. ocsigenserver
  342. ocsipersist
  343. ocsipersist-dbm
  344. ocsipersist-lib
  345. ocsipersist-pgsql
  346. ocsipersist-sqlite
  347. oframl
  348. ojs_base
  349. omigrate
  350. oneffs
  351. opam-check-npm-deps >= "4.1.0"
  352. opam-publish >= "3.0.0"
  353. opencage
  354. opentelemetry-client-cohttp-lwt
  355. opentelemetry-client-ocurl-lwt
  356. opentelemetry-cohttp-lwt >= "0.4"
  357. opentelemetry-lwt
  358. opium
  359. opium-graphql
  360. opium_kernel
  361. opomodoro
  362. order-i3-xfce
  363. ordma
  364. oskel >= "0.3.0"
  365. ounit-lwt < "2.2.0"
  366. ounit2-lwt
  367. owork
  368. ozulip
  369. paf
  370. paf-cohttp
  371. passage < "0.1.8"
  372. pcap-format < "0.5.2"
  373. petrol
  374. pgn_parser
  375. pgx_lwt
  376. pgx_lwt_mirage
  377. pgx_lwt_unix < "2.0"
  378. piaf < "0.2.0"
  379. picos >= "0.3.0" & < "0.5.0"
  380. picos_meta
  381. plebeia >= "2.0.0"
  382. plotkicadsch
  383. posix-getopt >= "4.0.2"
  384. ppx_defer >= "0.4.0"
  385. ppx_deriving_rpc
  386. ppx_rapper_lwt
  387. proc-smaps
  388. prof_spacetime
  389. prometheus
  390. prometheus-app
  391. promise_jsoo_lwt
  392. protocol-9p
  393. protocol-9p-unix
  394. proton
  395. pxshot
  396. qcow
  397. qcow-stream
  398. qcow-tool
  399. qcow-types
  400. qdrant < "0.2.0"
  401. qfs
  402. quests
  403. quickterface
  404. rawlink < "2.1"
  405. rawlink-lwt
  406. rdf_json_ld
  407. rdf_lwt
  408. redis-lwt
  409. reparse-lwt
  410. reparse-lwt-unix
  411. resource-pooling
  412. resp
  413. resp-mirage >= "0.10.0"
  414. resp-unix >= "0.10.0"
  415. resto
  416. resto-cohttp-client = "0.4"
  417. resto-cohttp-server = "0.4"
  418. resto-directory = "0.4"
  419. ringo-lwt
  420. river
  421. rock
  422. rpclib-js
  423. rpclib-lwt
  424. SZXX < "4.0.0"
  425. sanddb
  426. scgi
  427. sendmail-lwt
  428. sendmail-mirage
  429. serial
  430. server-reason-react
  431. session-cohttp-lwt
  432. session-cookie-lwt
  433. session-postgresql-lwt
  434. sessions
  435. shared-block-ring
  436. shared-memory-ring-lwt
  437. sherlodoc
  438. sihl < "0.2.0"
  439. slack
  440. slacko
  441. slipshow
  442. smtml >= "0.7.0"
  443. speed
  444. spin < "0.8.0"
  445. spoke
  446. statocaml
  447. stk
  448. stog
  449. swapfs
  450. syguslib-utils
  451. syndic >= "1.4" & < "1.6.0"
  452. tar-mirage
  453. tar-unix
  454. tcpip
  455. telegraml
  456. terminus
  457. testcontainers
  458. testo-lwt
  459. tidy_email
  460. tls >= "0.10.6" & < "0.16.0"
  461. tls-lwt
  462. tls-mirage
  463. tube
  464. tuntap
  465. twirp_cohttp_lwt_unix
  466. uring
  467. uspf
  468. uspf-lwt
  469. uspf-mirage
  470. utcp
  471. utop
  472. uwt
  473. vchan
  474. vchan-unix
  475. vchan-xen
  476. vercel
  477. vhd-format-lwt
  478. vmnet
  479. vue-jsoo < "0.3"
  480. wayland < "2.0"
  481. webauthn
  482. xen-evtchn
  483. xen-evtchn-unix
  484. xen-gnt
  485. xen-gnt-unix
  486. xenstore
  487. xenstore-tool
  488. xenstore_transport
  489. xlsx2csv
  490. yocaml_git
  491. yocaml_unix < "2.0.0"
  492. zarr-lwt
  493. zmq-lwt >= "5.2.1"

Conflicts

None