package lwt

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Promises and event-driven I/O

Install 

dune-project
 Dependency

github.com Edit opam file Versions (28)

Authors

  1. J
    Jérôme Vouillon
  2. J
    Jérémie Dimino

Maintainers

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

Sources

6.0.0-beta01.tar.gz
md5=6bb978c590433a218a53722b985a01d4
sha512=529c8c920716cf204efd60a2bad3f817eed6eed120a8e8a8dae763ab7f4c45799a74004d0d0a2b8ec08f37c81b77f1a4813426a25f256b254dfa846c86debe44

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: 15 Dec 2025

Dependencies (5)

  1. ocplib-endian
  2. dune-configurator
  3. cppo build & >= "1.1"
  4. ocaml >= "4.14"
  5. dune >= "3.15"

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 < "4.4.0" | >= "4.8.1"
  18. awsm-lwt
  19. azure-cosmos-db
  20. balancer
  21. bastet_lwt
  22. bistro
  23. brisk-reconciler
  24. brozip
  25. builder
  26. builder-web
  27. bun >= "0.3.3"
  28. cachet-lwt
  29. calculon
  30. caldav
  31. camltc
  32. canary
  33. capnp-rpc-lwt < "2.0"
  34. capnp-rpc-unix < "2.1"
  35. caqti-mirage
  36. carton < "1.0.0"
  37. carton-git
  38. carton-lwt
  39. catala-format >= "0.2.0"
  40. cf-lwt
  41. chamelon
  42. chamelon-unix
  43. chamo
  44. charrua-client
  45. charrua-unix
  46. chess_com_api
  47. clz
  48. cmdtui-lambda-term
  49. coap
  50. coap-server-lwt
  51. cohttp-curl-lwt
  52. cohttp-lwt
  53. cohttp-lwt-jsoo
  54. cohttp-lwt-unix
  55. cohttp-mirage
  56. cohttp-server-lwt-unix
  57. comby
  58. comby-semantic
  59. conan-lwt
  60. conduit-lwt
  61. conduit-lwt-unix
  62. cowabloga
  63. crunch
  64. cstruct-lwt
  65. csv-lwt
  66. ctypes >= "0.15.0" & < "0.21.1"
  67. ctypes-foreign >= "0.21.1"
  68. current
  69. current-albatross-deployer
  70. current_docker
  71. current_examples
  72. current_git
  73. current_github
  74. current_gitlab
  75. current_ocluster
  76. current_rpc
  77. current_slack
  78. current_web
  79. DkSDKFFIOCaml_Std
  80. dap
  81. data-encoding < "0.1.1"
  82. devkit >= "1.2"
  83. distributed-lwt
  84. dkim-bin < "0.8.0"
  85. dkim-lwt-unix
  86. dkim-mirage
  87. dlm
  88. dmarc
  89. dns-certify
  90. dns-cli
  91. dns-client < "7.0.3"
  92. dns-client-lwt
  93. dns-client-mirage
  94. dns-forward
  95. dns-forward-lwt-unix
  96. dns-lwt
  97. dns-mirage
  98. dns-resolver
  99. dns-server
  100. dns-stub
  101. dnssd
  102. docker_hub
  103. docteur >= "0.0.2"
  104. docteur-solo5
  105. docteur-unix >= "0.0.5"
  106. doi2bib
  107. dream
  108. dream-httpaf
  109. dream-pure
  110. dream-serve
  111. dropbox
  112. dune >= "3.17.2"
  113. dune-rpc-lwt
  114. earlybird
  115. elasticsearch-cli
  116. emoji = "2.0.0"
  117. equinoxe
  118. ethernet
  119. ez_api >= "1.2.0"
  120. ezcurl-lwt
  121. ezjs_min < "0.2"
  122. ezjsonm-lwt
  123. ezresto
  124. faraday-lwt
  125. faraday-lwt-unix
  126. fat-filesystem
  127. fiber-lwt
  128. fsevents-lwt
  129. fswatch_lwt
  130. gdbprofiler
  131. git
  132. git-cohttp
  133. git-cohttp-unix
  134. git-kv >= "0.2.0"
  135. git-mirage
  136. git-paf
  137. git-unix >= "3.2.0"
  138. github
  139. github-hooks
  140. github-unix >= "4.4.0"
  141. gitlab-unix
  142. gitlab_pipeline_notifier
  143. gluten-lwt
  144. gluten-lwt-unix < "0.4.0"
  145. gluten-mirage < "0.4.0"
  146. graphql-lwt
  147. gremlin
  148. grpc-lwt
  149. guardian
  150. gufo
  151. h1
  152. h1-lwt-unix
  153. h2-lwt
  154. h2-lwt-unix < "0.10.0"
  155. h2-mirage
  156. happy-eyeballs-lwt
  157. happy-eyeballs-mirage
  158. hidapi-lwt
  159. hiredis >= "0.6"
  160. hl_yaml
  161. hockmd
  162. http-lwt-client
  163. http-mirage-client
  164. http-multipart-formdata >= "2.0.0" & < "3.0.0"
  165. httpaf-lwt-unix
  166. httpun-lwt
  167. httpun-mirage
  168. httpun-ws-lwt
  169. hvsock
  170. i3ipc
  171. influxdb-lwt
  172. inotify >= "2.4"
  173. inquire < "0.3.0"
  174. interface-prime-lwt
  175. ip2location
  176. ip2locationio
  177. ip2whois
  178. ipv6-multicast-lwt
  179. irc-client-lwt
  180. irc-client-lwt-ssl
  181. irc-client-tls
  182. irmin
  183. irmin-bench
  184. irmin-chunk
  185. irmin-cli
  186. irmin-client
  187. irmin-containers
  188. irmin-fs
  189. irmin-git
  190. irmin-graphql
  191. irmin-http
  192. irmin-indexeddb
  193. irmin-layers
  194. irmin-mirage-git
  195. irmin-mirage-graphql
  196. irmin-pack
  197. irmin-server
  198. irmin-test
  199. irmin-unix
  200. irmin-watcher
  201. joolog
  202. jose < "0.9.0"
  203. js_of_ocaml-lwt >= "3.5.0"
  204. jsoo_broadcastchannel
  205. jsoo_storage
  206. jupyter
  207. jupyter-kernel
  208. kafka < "0.5"
  209. kafka_lwt
  210. kappa-library
  211. ke >= "0.5"
  212. kinetic-client
  213. kubecaml
  214. lambda-runtime
  215. lambda_streams_lwt
  216. launchd
  217. ldp
  218. learn-ocaml
  219. learn-ocaml-client
  220. ledgerwallet >= "0.4.0"
  221. letsencrypt
  222. letsencrypt-app
  223. letsencrypt-dns
  224. letters
  225. lichess_api
  226. links >= "0.9.1"
  227. llama
  228. lru_cache
  229. lwt-canceler
  230. lwt-dllist
  231. lwt-exit
  232. lwt-parallel
  233. lwt-pipe
  234. lwt-pipeline
  235. lwt-watcher
  236. lwt_camlp4
  237. lwt_direct
  238. lwt_ppx >= "6.0.0-beta01"
  239. lwt_react
  240. lwt_retry
  241. lwt_ssl
  242. mariadb >= "1.2.0"
  243. markup = "0.7.6"
  244. markup-lwt
  245. mdx
  246. mechaml
  247. mehari-lwt-unix
  248. mehari-mirage
  249. memtrace-mirage
  250. metrics-influx
  251. metrics-lwt
  252. metrics-unix
  253. mimic
  254. mindstorm-lwt
  255. mirage < "4.0.0"
  256. mirage-block >= "2.0.1"
  257. mirage-block-ccm
  258. mirage-block-combinators
  259. mirage-block-lwt
  260. mirage-block-partition
  261. mirage-block-ramdisk
  262. mirage-block-solo5
  263. mirage-block-unikraft
  264. mirage-block-unix >= "2.14.2"
  265. mirage-block-xen
  266. mirage-channel >= "4.0.1"
  267. mirage-channel-lwt
  268. mirage-clock-lwt
  269. mirage-clock-unix < "4.2.0"
  270. mirage-console-lwt
  271. mirage-crypto-rng < "0.11.3"
  272. mirage-crypto-rng-lwt
  273. mirage-crypto-rng-mirage
  274. mirage-device >= "2.0.0"
  275. mirage-flow >= "3.0.0"
  276. mirage-flow-combinators
  277. mirage-flow-lwt
  278. mirage-flow-unix
  279. mirage-fs >= "4.0.0"
  280. mirage-fs-lwt
  281. mirage-kv >= "3.0.1"
  282. mirage-kv-lwt
  283. mirage-kv-unix
  284. mirage-net >= "4.0.0"
  285. mirage-net-lwt
  286. mirage-net-macosx
  287. mirage-net-solo5
  288. mirage-net-unikraft
  289. mirage-net-unix
  290. mirage-net-xen
  291. mirage-profile
  292. mirage-protocols >= "7.0.0"
  293. mirage-protocols-lwt
  294. mirage-qubes
  295. mirage-qubes-ipv4
  296. mirage-runtime
  297. mirage-sleep
  298. mirage-solo5
  299. mirage-stack = "3.0.0"
  300. mirage-stack-lwt
  301. mirage-time >= "3.0.0"
  302. mirage-time-lwt
  303. mirage-time-unix
  304. mirage-types-lwt
  305. mirage-unikraft
  306. mirage-unix
  307. mirage-vnetif
  308. mirage-xen
  309. monorobot
  310. mqtt
  311. mrmime >= "0.5.0"
  312. multipart-form-data
  313. multipart_form >= "0.2.0" & < "0.4.0"
  314. multipart_form-cohttp-lwt < "0.6.0"
  315. multipart_form-lwt
  316. naboris
  317. nbd >= "4.0.3"
  318. nbd-tool
  319. nbd-unix
  320. nottui-lwt
  321. notty-community
  322. nproc
  323. nsq
  324. obuilder
  325. obus >= "1.2.1"
  326. ocluster-api
  327. ocluster-worker
  328. ocplib-resto
  329. ocsigenserver
  330. ocsipersist
  331. ocsipersist-dbm
  332. ocsipersist-lib
  333. ocsipersist-pgsql
  334. ocsipersist-sqlite
  335. octez-distributed-lwt-internal
  336. octez-internal-libs
  337. octez-l2-libs
  338. octez-libs
  339. octez-proto-libs
  340. octez-protocol-compiler
  341. octez-proxy-server
  342. octez-rpc-process
  343. octez-shell-libs
  344. octez-smart-rollup-wasm-benchmark-lib
  345. oframl
  346. ojs_base
  347. omigrate
  348. oneffs
  349. opencage
  350. opentelemetry-client-cohttp-lwt
  351. opentelemetry-cohttp-lwt >= "0.4"
  352. opentelemetry-lwt
  353. opium
  354. opium-graphql
  355. opium_kernel
  356. opomodoro
  357. order-i3-xfce
  358. ordma
  359. oskel >= "0.3.0"
  360. ounit-lwt < "2.2.0"
  361. ounit2-lwt
  362. owork
  363. ozulip
  364. paf
  365. paf-cohttp
  366. passage < "0.1.8"
  367. pcap-format < "0.5.2"
  368. petrol
  369. pgn_parser
  370. pgx_lwt
  371. pgx_lwt_mirage
  372. pgx_lwt_unix < "2.0"
  373. piaf < "0.2.0"
  374. picos_meta
  375. plebeia >= "2.0.0"
  376. plotkicadsch
  377. ppx_defer >= "0.4.0"
  378. ppx_deriving_rpc
  379. ppx_rapper_lwt
  380. proc-smaps
  381. prof_spacetime
  382. prometheus
  383. prometheus-app
  384. promise_jsoo_lwt
  385. protocol-9p
  386. protocol-9p-unix
  387. proton
  388. qcow
  389. qcow-stream
  390. qcow-tool
  391. qcow-types
  392. qfs >= "0.5"
  393. quests
  394. rawlink < "2.1"
  395. rawlink-lwt
  396. rdf_json_ld
  397. rdf_lwt
  398. redis-lwt
  399. reparse-lwt
  400. reparse-lwt-unix
  401. resource-pooling
  402. resp
  403. resp-mirage >= "0.10.0"
  404. resp-unix >= "0.10.0"
  405. resto
  406. resto-cohttp-client = "0.4"
  407. resto-cohttp-server = "0.4"
  408. resto-directory = "0.4"
  409. riak
  410. ringo-lwt
  411. river
  412. rock
  413. rpclib-js
  414. rpclib-lwt
  415. SZXX < "4.0.0"
  416. sanddb
  417. scgi
  418. sendmail-lwt
  419. sendmail-mirage
  420. serial
  421. server-reason-react
  422. session-cohttp-lwt
  423. session-cookie-lwt
  424. session-postgresql-lwt
  425. sessions
  426. shared-block-ring
  427. shared-memory-ring-lwt
  428. sherlodoc
  429. sihl < "0.2.0"
  430. slack
  431. slacko
  432. slipshow
  433. smtml >= "0.7.0"
  434. speed
  435. spin < "0.8.0"
  436. spoke
  437. statocaml
  438. stk
  439. stog
  440. swapfs
  441. syguslib-utils
  442. syndic >= "1.4" & < "1.6.0"
  443. tar-mirage
  444. tar-unix
  445. tcpip
  446. telegraml
  447. terminus
  448. testo-lwt
  449. tezos-base >= "16.0"
  450. tezos-clic >= "16.0"
  451. tezos-crypto >= "16.0"
  452. tezos-crypto-dal
  453. tezos-error-monad >= "16.0"
  454. tezos-lwt-result-stdlib
  455. tezos-p2p = "12.3"
  456. tezos-protocol-environment
  457. tezos-proxy >= "17.3"
  458. tezos-stdlib
  459. tezos-stdlib-unix >= "16.0"
  460. tezos-test-helpers >= "12.3"
  461. tezos-webassembly-interpreter-extra
  462. tidy_email
  463. timmy-lwt
  464. tls >= "0.10.6" & < "0.16.0"
  465. tls-lwt
  466. tls-mirage
  467. tube
  468. tuntap
  469. twirp_cohttp_lwt_unix
  470. uring
  471. uspf
  472. uspf-lwt
  473. uspf-mirage
  474. utop
  475. uwt
  476. vchan
  477. vchan-unix
  478. vchan-xen
  479. vercel
  480. vhd-format-lwt
  481. vmnet
  482. vpnkit
  483. vue-jsoo < "0.3"
  484. wayland < "2.0"
  485. webauthn
  486. xen-evtchn
  487. xen-evtchn-unix
  488. xen-gnt
  489. xen-gnt-unix
  490. xenstore
  491. xenstore-tool
  492. xenstore_transport
  493. xlsx2csv
  494. yocaml_git
  495. yocaml_unix < "2.0.0"
  496. zarr-lwt
  497. zmq-lwt >= "5.2.1"

Conflicts

None