package lwt

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Promises and event-driven I/O

Install 

dune-project
 Dependency

github.com Edit opam file Versions (34)

Authors

  1. J
    Jérôme Vouillon
  2. J
    Jérémie Dimino

Maintainers

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

Sources

5.10.1.tar.gz
md5=3550f2448bf94379ecd3d480eb8cb070
sha512=361b4fe8b1613683a0cd89fea08d9ae1615f84e771363ba97843c2dda5c3f45b4a4b6c048c8d79fa58d609c45a7e1dfa2b3e9873d02bac82934fd892f8f4fce1

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 Jun 2026

Dependencies (5)

  1. ocplib-endian
  2. dune-configurator
  3. cppo build & >= "1.1"
  4. ocaml >= "4.08"
  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 >= "4.8.1"
  18. awskit-lwt
  19. awskit-lwt-unix
  20. awskit-s3-lwt
  21. awskit-s3-lwt-unix
  22. awsm-lwt
  23. awso-lwt
  24. azure-cosmos-db < "0.4.0"
  25. azure-cosmos-db-lwt
  26. balancer
  27. bastet_lwt
  28. bimage-lwt
  29. bistro
  30. bizowie-api
  31. brisk-reconciler
  32. builder
  33. builder-web
  34. bun >= "0.3.3"
  35. cachet-lwt
  36. calculon
  37. caldav
  38. camltc
  39. canary
  40. capnp-rpc-lwt < "2.0"
  41. capnp-rpc-unix < "2.1"
  42. caqti-lwt
  43. caqti-mirage
  44. carton < "1.0.0"
  45. carton-git
  46. carton-lwt
  47. catala-format >= "0.2.0"
  48. cf-lwt
  49. chamelon
  50. chamelon-unix
  51. chamo
  52. charrua-client
  53. charrua-unix
  54. chess_com_api
  55. ciao_lwt
  56. clz
  57. cmdtui-lambda-term
  58. coap
  59. coap-server-lwt
  60. cohttp-curl-lwt
  61. cohttp-lwt
  62. cohttp-lwt-jsoo
  63. cohttp-lwt-unix
  64. cohttp-mirage
  65. cohttp-server-lwt-unix
  66. comby
  67. comby-semantic
  68. conan-lwt
  69. conduit-lwt
  70. conduit-lwt-unix
  71. cowabloga
  72. crunch
  73. cstruct-lwt
  74. csv-lwt
  75. ctypes >= "0.15.0" & < "0.21.1"
  76. ctypes-foreign >= "0.21.1"
  77. curl_lwt
  78. current
  79. current-albatross-deployer
  80. current_docker
  81. current_examples
  82. current_git
  83. current_github
  84. current_gitlab
  85. current_ocluster
  86. current_rpc
  87. current_slack
  88. current_web
  89. dap
  90. data-encoding < "0.1.1"
  91. devkit >= "1.2"
  92. distributed-lwt
  93. dkim-bin < "0.8.0"
  94. dkim-lwt-unix
  95. dkim-mirage
  96. dlm
  97. dmarc
  98. dns-certify
  99. dns-cli
  100. dns-client < "7.0.3"
  101. dns-client-lwt
  102. dns-client-mirage
  103. dns-forward
  104. dns-forward-lwt-unix
  105. dns-lwt
  106. dns-mirage
  107. dns-resolver
  108. dns-server
  109. dns-stub
  110. dnsrobot
  111. dnssd
  112. docker_hub
  113. docteur >= "0.0.2"
  114. docteur-solo5
  115. docteur-unix >= "0.0.5"
  116. doi2bib
  117. dream
  118. dream-httpaf
  119. dream-pure
  120. dream-serve < "1.0.1"
  121. dropbox
  122. dune >= "3.17.2"
  123. dune-rpc-lwt
  124. earlybird
  125. elasticsearch-cli
  126. emoji = "2.0.0"
  127. equinoxe
  128. ethernet
  129. ez_api >= "1.2.0" & < "3.0.0"
  130. ezcurl-lwt
  131. ezjs_min < "0.2"
  132. ezjsonm-lwt
  133. ezresto
  134. ezresto-directory >= "0.5"
  135. faraday-lwt
  136. faraday-lwt-unix
  137. fat-filesystem
  138. fiber-lwt
  139. fsevents-lwt
  140. fswatch_lwt
  141. fuseau-lwt
  142. gdbprofiler
  143. git
  144. git-cohttp
  145. git-cohttp-unix
  146. git-kv >= "0.2.0"
  147. git-mirage
  148. git-paf
  149. git-unix >= "3.2.0"
  150. github
  151. github-hooks
  152. github-unix >= "4.4.0"
  153. gitlab-unix
  154. gitlab_pipeline_notifier
  155. gluten-lwt
  156. gluten-lwt-unix < "0.4.0"
  157. gluten-mirage < "0.4.0"
  158. graphql-lwt
  159. gremlin
  160. grpc-lwt
  161. guardian
  162. gufo
  163. h1
  164. h1-lwt-unix
  165. h2-lwt
  166. h2-lwt-unix < "0.10.0"
  167. h2-mirage
  168. happy-eyeballs-lwt
  169. happy-eyeballs-mirage
  170. hidapi-lwt
  171. hiredis >= "0.6"
  172. hl_yaml
  173. hockmd
  174. http-lwt-client
  175. http-mirage-client
  176. http-multipart-formdata >= "2.0.0" & < "3.0.0"
  177. httpaf-lwt-unix
  178. httpun-lwt
  179. httpun-mirage
  180. httpun-ws-lwt
  181. hvsock
  182. i3ipc
  183. influxdb-lwt
  184. inotify >= "2.4"
  185. inquire < "0.3.0"
  186. interface-prime-lwt
  187. ip2location
  188. ip2locationio
  189. ip2whois
  190. ipv6-multicast-lwt
  191. irc-client-lwt
  192. irc-client-lwt-ssl
  193. irc-client-tls
  194. irmin
  195. irmin-bench
  196. irmin-chunk
  197. irmin-cli
  198. irmin-client
  199. irmin-containers
  200. irmin-fs
  201. irmin-git
  202. irmin-graphql
  203. irmin-http
  204. irmin-indexeddb
  205. irmin-layers
  206. irmin-mirage-git
  207. irmin-mirage-graphql
  208. irmin-pack
  209. irmin-server
  210. irmin-test
  211. irmin-unix
  212. irmin-watcher
  213. joolog
  214. jose < "0.9.0"
  215. js_of_ocaml-lwt
  216. jsoo_broadcastchannel
  217. jsoo_storage
  218. jupyter
  219. jupyter-kernel
  220. kafka < "0.5"
  221. kafka_lwt
  222. kappa-library
  223. ke >= "0.5"
  224. kinetic-client
  225. kubecaml
  226. lambda-runtime
  227. lambda-term
  228. lambda_streams_lwt
  229. launchd
  230. ldp
  231. learn-ocaml
  232. learn-ocaml-client
  233. ledgerwallet >= "0.4.0"
  234. letsencrypt < "2.0.0"
  235. letsencrypt-app
  236. letsencrypt-dns < "2.0.0"
  237. letters
  238. lichess_api
  239. links
  240. linol-lwt
  241. llama
  242. lru_cache
  243. lwt-canceler
  244. lwt-dllist
  245. lwt-exit
  246. lwt-parallel
  247. lwt-pipe
  248. lwt-pipeline
  249. lwt-watcher
  250. lwt_camlp4
  251. lwt_domain
  252. lwt_eio < "0.6"
  253. lwt_glib
  254. lwt_log
  255. lwt_ppx < "6.0.0~beta01"
  256. lwt_react
  257. lwt_retry
  258. lwt_ssl
  259. mariadb >= "1.2.0"
  260. markdown_monolith
  261. markup = "0.7.6"
  262. markup-lwt
  263. mdx
  264. mechaml
  265. mehari-lwt-unix
  266. mehari-mirage
  267. memtrace-mirage
  268. metrics-influx
  269. metrics-lwt
  270. metrics-unix
  271. migra
  272. mimic
  273. mindstorm-lwt
  274. mirage < "4.0.0"
  275. mirage-block >= "2.0.1"
  276. mirage-block-ccm
  277. mirage-block-combinators
  278. mirage-block-lwt
  279. mirage-block-partition
  280. mirage-block-ramdisk
  281. mirage-block-solo5
  282. mirage-block-unikraft
  283. mirage-block-unix >= "2.14.2"
  284. mirage-block-xen
  285. mirage-channel >= "4.0.1"
  286. mirage-channel-lwt
  287. mirage-clock-lwt
  288. mirage-clock-unix < "4.2.0"
  289. mirage-console-lwt
  290. mirage-crypto-rng < "0.11.3"
  291. mirage-crypto-rng-lwt
  292. mirage-crypto-rng-mirage
  293. mirage-device >= "2.0.0"
  294. mirage-flow >= "3.0.0"
  295. mirage-flow-combinators
  296. mirage-flow-lwt
  297. mirage-flow-unix
  298. mirage-fs >= "4.0.0"
  299. mirage-fs-lwt
  300. mirage-kv >= "3.0.1"
  301. mirage-kv-lwt
  302. mirage-kv-unix
  303. mirage-net >= "4.0.0"
  304. mirage-net-lwt
  305. mirage-net-macosx
  306. mirage-net-solo5
  307. mirage-net-unikraft
  308. mirage-net-unix
  309. mirage-net-xen
  310. mirage-profile
  311. mirage-protocols >= "7.0.0"
  312. mirage-protocols-lwt
  313. mirage-qubes
  314. mirage-qubes-ipv4
  315. mirage-runtime
  316. mirage-sleep
  317. mirage-solo5
  318. mirage-stack = "3.0.0"
  319. mirage-stack-lwt
  320. mirage-time >= "3.0.0"
  321. mirage-time-lwt
  322. mirage-time-unix
  323. mirage-types-lwt
  324. mirage-unikraft
  325. mirage-unix
  326. mirage-vnetif
  327. mirage-xen
  328. monorobot
  329. moonpool-lwt
  330. mqtt
  331. mrmime >= "0.5.0"
  332. multipart-form-data
  333. multipart_form >= "0.2.0" & < "0.4.0"
  334. multipart_form-cohttp-lwt < "0.6.0"
  335. multipart_form-lwt
  336. mwt
  337. naboris
  338. nbd >= "4.0.3"
  339. nbd-tool
  340. nbd-unix
  341. neo4j_bolt
  342. nocrypto
  343. nottui-lwt
  344. notty-community
  345. nproc
  346. nsq
  347. obuilder
  348. obus >= "1.2.1"
  349. ocaml-ai-sdk
  350. ocluster
  351. ocluster-api
  352. ocluster-worker
  353. ocplib-resto
  354. ocsigenserver
  355. ocsipersist
  356. ocsipersist-dbm
  357. ocsipersist-lib
  358. ocsipersist-pgsql
  359. ocsipersist-sqlite
  360. oframl
  361. ojs_base
  362. omigrate
  363. oneffs
  364. opam-check-npm-deps >= "4.1.0"
  365. opam-publish >= "3.0.0"
  366. opencage
  367. opentelemetry-client-cohttp-lwt
  368. opentelemetry-client-ocurl-lwt
  369. opentelemetry-cohttp-lwt >= "0.4"
  370. opentelemetry-lwt
  371. opium
  372. opium-graphql
  373. opium_kernel
  374. opomodoro
  375. order-i3-xfce
  376. ordma
  377. oskel >= "0.3.0"
  378. ounit-lwt < "2.2.0"
  379. ounit2-lwt
  380. owork
  381. ozulip
  382. paf
  383. paf-cohttp
  384. passage < "0.1.8"
  385. pcap-format < "0.5.2"
  386. petrol
  387. pgn_parser
  388. pgx_lwt
  389. pgx_lwt_mirage
  390. pgx_lwt_unix < "2.0"
  391. piaf < "0.2.0"
  392. picos >= "0.3.0" & < "0.5.0"
  393. picos_lwt
  394. picos_meta
  395. plebeia >= "2.0.0"
  396. plist-xml-lwt
  397. plotkicadsch
  398. posix-getopt >= "4.0.2"
  399. ppx_defer >= "0.4.0"
  400. ppx_deriving_rpc
  401. ppx_rapper_lwt
  402. proc-smaps
  403. prof_spacetime
  404. prometheus
  405. prometheus-app
  406. promise_jsoo_lwt
  407. protocol-9p
  408. protocol-9p-unix
  409. proton
  410. pxshot
  411. qcow
  412. qcow-stream
  413. qcow-tool
  414. qcow-types
  415. qdrant < "0.2.0"
  416. qfs
  417. quests
  418. quickterface
  419. rawlink < "2.1"
  420. rawlink-lwt
  421. rdf_json_ld
  422. rdf_lwt
  423. redis-lwt
  424. reparse-lwt
  425. reparse-lwt-unix
  426. resource-pooling
  427. resp
  428. resp-mirage >= "0.10.0"
  429. resp-unix >= "0.10.0"
  430. resto
  431. resto-cohttp-client >= "0.4"
  432. resto-cohttp-self-serving-client
  433. resto-cohttp-server >= "0.4" & < "0.6" | >= "0.9"
  434. resto-directory >= "0.4"
  435. ringo-lwt
  436. river
  437. rock
  438. rpclib-js
  439. rpclib-lwt
  440. SZXX < "4.0.0"
  441. sanddb
  442. scgi
  443. sendmail-lwt
  444. sendmail-mirage
  445. serial
  446. server-reason-react
  447. session-cohttp-lwt
  448. session-cookie-lwt
  449. session-postgresql-lwt
  450. sessions
  451. shared-block-ring
  452. shared-memory-ring-lwt
  453. sherlodoc
  454. sihl < "0.2.0"
  455. slack
  456. slacko
  457. slipshow
  458. smtml >= "0.7.0"
  459. speed
  460. spin < "0.8.0"
  461. spoke
  462. statocaml
  463. stk
  464. stog
  465. swapfs
  466. syguslib-utils
  467. syndic >= "1.4" & < "1.6.0"
  468. tar-mirage
  469. tar-unix
  470. tcpip
  471. telegraml
  472. terminus
  473. testcontainers
  474. testo-lwt
  475. tezt
  476. tidy_email
  477. timmy-lwt
  478. tls >= "0.10.6" & < "0.16.0"
  479. tls-lwt
  480. tls-mirage
  481. tube
  482. tuntap
  483. twirp_cohttp_lwt_unix
  484. uring
  485. uspf
  486. uspf-lwt
  487. uspf-mirage
  488. utcp
  489. utop
  490. uwt
  491. vchan
  492. vchan-unix
  493. vchan-xen
  494. vercel
  495. vhd-format-lwt
  496. vmnet
  497. vue-jsoo < "0.3"
  498. wayland < "2.0"
  499. webauthn
  500. xen-evtchn
  501. xen-evtchn-unix
  502. xen-gnt
  503. xen-gnt-unix
  504. xenstore
  505. xenstore-tool
  506. xenstore_transport
  507. xlsx2csv
  508. yocaml_git
  509. yocaml_unix < "2.0.0"
  510. zarr-lwt
  511. zmq-lwt >= "5.2.1"

Conflicts

None