package lwt

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Promises and event-driven I/O

Install 

dune-project
 Dependency

github.com Edit opam file Versions (33)

Authors

  1. J
    Jérôme Vouillon
  2. J
    Jérémie Dimino

Maintainers

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

Sources

5.10.0.tar.gz
md5=dba3f8d8db1b9bed9f3a24385cc48e2b
sha512=6d25ebc6d011e75ff6ce6d1b0821be1aacbdebc2fbb26130edd43f20c0d1874bbcb6618003600fc80006a898434118795f691322a2455de11dfa23a868d6a110

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 May 2026

Dependencies (5)

  1. ocplib-endian
  2. dune-configurator
  3. cppo build & >= "1.1"
  4. ocaml >= "4.08" & < "5.5"
  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. awsm-lwt
  19. awso-lwt
  20. azure-cosmos-db < "0.4.0"
  21. azure-cosmos-db-lwt
  22. balancer
  23. bastet_lwt
  24. bimage-lwt
  25. bistro
  26. bizowie-api
  27. brisk-reconciler
  28. builder
  29. builder-web
  30. bun >= "0.3.3"
  31. cachet-lwt
  32. calculon
  33. caldav
  34. camltc
  35. canary
  36. capnp-rpc-lwt < "2.0"
  37. capnp-rpc-unix < "2.1"
  38. caqti-lwt
  39. caqti-mirage
  40. carton < "1.0.0"
  41. carton-git
  42. carton-lwt
  43. catala-format >= "0.2.0"
  44. cf-lwt
  45. chamelon
  46. chamelon-unix
  47. chamo
  48. charrua-client
  49. charrua-unix
  50. chess_com_api
  51. ciao_lwt
  52. clz
  53. cmdtui-lambda-term
  54. coap
  55. coap-server-lwt
  56. cohttp-curl-lwt
  57. cohttp-lwt
  58. cohttp-lwt-jsoo
  59. cohttp-lwt-unix
  60. cohttp-mirage
  61. cohttp-server-lwt-unix
  62. comby
  63. comby-semantic
  64. conan-lwt
  65. conduit-lwt
  66. conduit-lwt-unix
  67. cowabloga
  68. crunch
  69. cstruct-lwt
  70. csv-lwt
  71. ctypes >= "0.15.0" & < "0.21.1"
  72. ctypes-foreign >= "0.21.1"
  73. curl_lwt
  74. current
  75. current-albatross-deployer
  76. current_docker
  77. current_examples
  78. current_git
  79. current_github
  80. current_gitlab
  81. current_ocluster
  82. current_rpc
  83. current_slack
  84. current_web
  85. dap
  86. data-encoding < "0.1.1"
  87. devkit >= "1.2"
  88. distributed-lwt
  89. dkim-bin < "0.8.0"
  90. dkim-lwt-unix
  91. dkim-mirage
  92. dlm
  93. dmarc
  94. dns-certify
  95. dns-cli
  96. dns-client < "7.0.3"
  97. dns-client-lwt
  98. dns-client-mirage
  99. dns-forward
  100. dns-forward-lwt-unix
  101. dns-lwt
  102. dns-mirage
  103. dns-resolver
  104. dns-server
  105. dns-stub
  106. dnsrobot
  107. dnssd
  108. docker_hub
  109. docteur >= "0.0.2"
  110. docteur-solo5
  111. docteur-unix >= "0.0.5"
  112. doi2bib
  113. dream
  114. dream-httpaf
  115. dream-pure
  116. dream-serve < "1.0.1"
  117. dropbox
  118. dune >= "3.17.2"
  119. dune-rpc-lwt
  120. earlybird
  121. elasticsearch-cli
  122. emoji = "2.0.0"
  123. equinoxe
  124. ethernet
  125. ez_api >= "1.2.0"
  126. ezcurl-lwt
  127. ezjs_min < "0.2"
  128. ezjsonm-lwt
  129. ezresto
  130. ezresto-directory >= "0.5"
  131. faraday-lwt
  132. faraday-lwt-unix
  133. fat-filesystem
  134. fiber-lwt
  135. fsevents-lwt
  136. fswatch_lwt
  137. fuseau-lwt
  138. gdbprofiler
  139. git
  140. git-cohttp
  141. git-cohttp-unix
  142. git-kv >= "0.2.0"
  143. git-mirage
  144. git-paf
  145. git-unix >= "3.2.0"
  146. github
  147. github-hooks
  148. github-unix >= "4.4.0"
  149. gitlab-unix
  150. gitlab_pipeline_notifier
  151. gluten-lwt
  152. gluten-lwt-unix < "0.4.0"
  153. gluten-mirage < "0.4.0"
  154. graphql-lwt
  155. gremlin
  156. grpc-lwt
  157. guardian
  158. gufo
  159. h1
  160. h1-lwt-unix
  161. h2-lwt
  162. h2-lwt-unix < "0.10.0"
  163. h2-mirage
  164. happy-eyeballs-lwt
  165. happy-eyeballs-mirage
  166. hidapi-lwt
  167. hiredis >= "0.6"
  168. hl_yaml
  169. hockmd
  170. http-lwt-client
  171. http-mirage-client
  172. http-multipart-formdata >= "2.0.0" & < "3.0.0"
  173. httpaf-lwt-unix
  174. httpun-lwt
  175. httpun-mirage
  176. httpun-ws-lwt
  177. hvsock
  178. i3ipc
  179. influxdb-lwt
  180. inotify >= "2.4"
  181. inquire < "0.3.0"
  182. interface-prime-lwt
  183. ip2location
  184. ip2locationio
  185. ip2whois
  186. ipv6-multicast-lwt
  187. irc-client-lwt
  188. irc-client-lwt-ssl
  189. irc-client-tls
  190. irmin
  191. irmin-bench
  192. irmin-chunk
  193. irmin-cli
  194. irmin-client
  195. irmin-containers
  196. irmin-fs
  197. irmin-git
  198. irmin-graphql
  199. irmin-http
  200. irmin-indexeddb
  201. irmin-layers
  202. irmin-mirage-git
  203. irmin-mirage-graphql
  204. irmin-pack
  205. irmin-server
  206. irmin-test
  207. irmin-unix
  208. irmin-watcher
  209. joolog
  210. jose < "0.9.0"
  211. js_of_ocaml-lwt
  212. jsoo_broadcastchannel
  213. jsoo_storage
  214. jupyter
  215. jupyter-kernel
  216. kafka < "0.5"
  217. kafka_lwt
  218. kappa-library
  219. ke >= "0.5"
  220. kinetic-client
  221. kubecaml
  222. lambda-runtime
  223. lambda-term
  224. lambda_streams_lwt
  225. launchd
  226. ldp
  227. learn-ocaml
  228. learn-ocaml-client
  229. ledgerwallet >= "0.4.0"
  230. letsencrypt < "2.0.0"
  231. letsencrypt-app
  232. letsencrypt-dns < "2.0.0"
  233. letters
  234. lichess_api
  235. links
  236. linol-lwt
  237. llama
  238. lru_cache
  239. lwt-canceler
  240. lwt-dllist
  241. lwt-exit
  242. lwt-parallel
  243. lwt-pipe
  244. lwt-pipeline
  245. lwt-watcher
  246. lwt_camlp4
  247. lwt_domain
  248. lwt_eio < "0.6"
  249. lwt_glib
  250. lwt_log
  251. lwt_ppx < "6.0.0~beta01"
  252. lwt_react
  253. lwt_retry
  254. lwt_ssl
  255. mariadb >= "1.2.0"
  256. markdown_monolith
  257. markup = "0.7.6"
  258. markup-lwt
  259. mdx
  260. mechaml
  261. mehari-lwt-unix
  262. mehari-mirage
  263. memtrace-mirage
  264. metrics-influx
  265. metrics-lwt
  266. metrics-unix
  267. mimic
  268. mindstorm-lwt
  269. mirage < "4.0.0"
  270. mirage-block >= "2.0.1"
  271. mirage-block-ccm
  272. mirage-block-combinators
  273. mirage-block-lwt
  274. mirage-block-partition
  275. mirage-block-ramdisk
  276. mirage-block-solo5
  277. mirage-block-unikraft
  278. mirage-block-unix >= "2.14.2"
  279. mirage-block-xen
  280. mirage-channel >= "4.0.1"
  281. mirage-channel-lwt
  282. mirage-clock-lwt
  283. mirage-clock-unix < "4.2.0"
  284. mirage-console-lwt
  285. mirage-crypto-rng < "0.11.3"
  286. mirage-crypto-rng-lwt
  287. mirage-crypto-rng-mirage
  288. mirage-device >= "2.0.0"
  289. mirage-flow >= "3.0.0"
  290. mirage-flow-combinators
  291. mirage-flow-lwt
  292. mirage-flow-unix
  293. mirage-fs >= "4.0.0"
  294. mirage-fs-lwt
  295. mirage-kv >= "3.0.1"
  296. mirage-kv-lwt
  297. mirage-kv-unix
  298. mirage-net >= "4.0.0"
  299. mirage-net-lwt
  300. mirage-net-macosx
  301. mirage-net-solo5
  302. mirage-net-unikraft
  303. mirage-net-unix
  304. mirage-net-xen
  305. mirage-profile
  306. mirage-protocols >= "7.0.0"
  307. mirage-protocols-lwt
  308. mirage-qubes
  309. mirage-qubes-ipv4
  310. mirage-runtime
  311. mirage-sleep
  312. mirage-solo5
  313. mirage-stack = "3.0.0"
  314. mirage-stack-lwt
  315. mirage-time >= "3.0.0"
  316. mirage-time-lwt
  317. mirage-time-unix
  318. mirage-types-lwt
  319. mirage-unikraft
  320. mirage-unix
  321. mirage-vnetif
  322. mirage-xen
  323. monorobot
  324. moonpool-lwt
  325. mqtt
  326. mrmime >= "0.5.0"
  327. multipart-form-data
  328. multipart_form >= "0.2.0" & < "0.4.0"
  329. multipart_form-cohttp-lwt < "0.6.0"
  330. multipart_form-lwt
  331. mwt
  332. naboris
  333. nbd >= "4.0.3"
  334. nbd-tool
  335. nbd-unix
  336. neo4j_bolt
  337. nocrypto
  338. nottui-lwt
  339. notty-community
  340. nproc
  341. nsq
  342. obuilder
  343. obus >= "1.2.1"
  344. ocaml-ai-sdk
  345. ocluster
  346. ocluster-api
  347. ocluster-worker
  348. ocplib-resto
  349. ocsigenserver
  350. ocsipersist
  351. ocsipersist-dbm
  352. ocsipersist-lib
  353. ocsipersist-pgsql
  354. ocsipersist-sqlite
  355. oframl
  356. ojs_base
  357. omigrate
  358. oneffs
  359. opam-check-npm-deps >= "4.1.0"
  360. opam-publish >= "3.0.0"
  361. opencage
  362. opentelemetry-client-cohttp-lwt
  363. opentelemetry-client-ocurl-lwt
  364. opentelemetry-cohttp-lwt >= "0.4"
  365. opentelemetry-lwt
  366. opium
  367. opium-graphql
  368. opium_kernel
  369. opomodoro
  370. order-i3-xfce
  371. ordma
  372. oskel >= "0.3.0"
  373. ounit-lwt < "2.2.0"
  374. ounit2-lwt
  375. owork
  376. ozulip
  377. paf
  378. paf-cohttp
  379. passage < "0.1.8"
  380. pcap-format < "0.5.2"
  381. petrol
  382. pgn_parser
  383. pgx_lwt
  384. pgx_lwt_mirage
  385. pgx_lwt_unix < "2.0"
  386. piaf < "0.2.0"
  387. picos >= "0.3.0" & < "0.5.0"
  388. picos_lwt
  389. picos_meta
  390. plebeia >= "2.0.0"
  391. plist-xml-lwt
  392. plotkicadsch
  393. posix-getopt >= "4.0.2"
  394. ppx_defer >= "0.4.0"
  395. ppx_deriving_rpc
  396. ppx_rapper_lwt
  397. proc-smaps
  398. prof_spacetime
  399. prometheus
  400. prometheus-app
  401. promise_jsoo_lwt
  402. protocol-9p
  403. protocol-9p-unix
  404. proton
  405. pxshot
  406. qcow
  407. qcow-stream
  408. qcow-tool
  409. qcow-types
  410. qdrant < "0.2.0"
  411. qfs
  412. quests
  413. quickterface
  414. rawlink < "2.1"
  415. rawlink-lwt
  416. rdf_json_ld
  417. rdf_lwt
  418. redis-lwt
  419. reparse-lwt
  420. reparse-lwt-unix
  421. resource-pooling
  422. resp
  423. resp-mirage >= "0.10.0"
  424. resp-unix >= "0.10.0"
  425. resto
  426. resto-cohttp-client >= "0.4"
  427. resto-cohttp-self-serving-client
  428. resto-cohttp-server >= "0.4" & < "0.6" | >= "0.9"
  429. resto-directory >= "0.4"
  430. ringo-lwt
  431. river
  432. rock
  433. rpclib-js
  434. rpclib-lwt
  435. SZXX < "4.0.0"
  436. sanddb
  437. scgi
  438. sendmail-lwt
  439. sendmail-mirage
  440. serial
  441. server-reason-react
  442. session-cohttp-lwt
  443. session-cookie-lwt
  444. session-postgresql-lwt
  445. sessions
  446. shared-block-ring
  447. shared-memory-ring-lwt
  448. sherlodoc
  449. sihl < "0.2.0"
  450. slack
  451. slacko
  452. slipshow
  453. smtml >= "0.7.0"
  454. speed
  455. spin < "0.8.0"
  456. spoke
  457. statocaml
  458. stk
  459. stog
  460. swapfs
  461. syguslib-utils
  462. syndic >= "1.4" & < "1.6.0"
  463. tar-mirage
  464. tar-unix
  465. tcpip
  466. telegraml
  467. terminus
  468. testcontainers
  469. testo-lwt
  470. tezt
  471. tidy_email
  472. timmy-lwt
  473. tls >= "0.10.6" & < "0.16.0"
  474. tls-lwt
  475. tls-mirage
  476. tube
  477. tuntap
  478. twirp_cohttp_lwt_unix
  479. uring
  480. uspf
  481. uspf-lwt
  482. uspf-mirage
  483. utcp
  484. utop
  485. uwt
  486. vchan
  487. vchan-unix
  488. vchan-xen
  489. vercel
  490. vhd-format-lwt
  491. vmnet
  492. vue-jsoo < "0.3"
  493. wayland < "2.0"
  494. webauthn
  495. xen-evtchn
  496. xen-evtchn-unix
  497. xen-gnt
  498. xen-gnt-unix
  499. xenstore
  500. xenstore-tool
  501. xenstore_transport
  502. xlsx2csv
  503. yocaml_git
  504. yocaml_unix < "2.0.0"
  505. zarr-lwt
  506. zmq-lwt >= "5.2.1"

Conflicts

None