package lwt

  1. Overview
  2. Docs
Promises and event-driven I/O

Install

Dune Dependency

Authors

Maintainers

Sources

5.7.0.tar.gz
md5=737039d29d45b2d2b35db6931c8d75c6
sha512=42e629920783428673b99c9d7a639237c9e6b35079b5d907bc67e7ea506acf9edadc48cec580bdcfd2410ed9412bf5e6bcc8b09de2fa7d35ce1490973d05ddd1

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: 17 Aug 2023

README

Lwt

Lwt is a concurrent programming library for OCaml. It provides a single data type: the promise, which is a value that will become determined in the future. Creating a promise spawns a computation. When that computation is I/O, Lwt runs it in parallel with your OCaml code.

OCaml code, including creating and waiting on promises, is run in a single thread by default, so you don't have to worry about locking or preemption. You can detach code to be run in separate threads on an opt-in basis.

Here is a simplistic Lwt program which requests the Google front page, and fails if the request is not completed in five seconds:

open Lwt.Syntax

let () =
  let request =
    let* addresses = Lwt_unix.getaddrinfo "google.com" "80" [] in
    let google = Lwt_unix.((List.hd addresses).ai_addr) in

    Lwt_io.(with_connection google (fun (incoming, outgoing) ->
      let* () = write outgoing "GET / HTTP/1.1\r\n" in
      let* () = write outgoing "Connection: close\r\n\r\n" in
      let* response = read incoming in
      Lwt.return (Some response)))
  in

  let timeout =
    let* () = Lwt_unix.sleep 5. in
    Lwt.return None
  in

  match Lwt_main.run (Lwt.pick [request; timeout]) with
  | Some response -> print_string response
  | None -> prerr_endline "Request timed out"; exit 1

(* ocamlfind opt -package lwt.unix -linkpkg example.ml && ./a.out *)

In the program, functions such as Lwt_io.write create promises. The let* ... in construct is used to wait for a promise to become determined; the code after in is scheduled to run in a "callback." Lwt.pick races promises against each other, and behaves as the first one to complete. Lwt_main.run forces the whole promise-computation network to be executed. All the visible OCaml code is run in a single thread, but Lwt internally uses a combination of worker threads and non-blocking file descriptors to resolve in parallel the promises that do I/O.


Overview

Lwt compiles to native code on Linux, macOS, Windows, and other systems. It's also routinely compiled to JavaScript for the front end and Node by js_of_ocaml.

In Lwt,

  • The core library Lwt provides promises...

  • ...and a few pure-OCaml helpers, such as promise-friendly mutexes, condition variables, and mvars.

  • There is a big Unix binding, Lwt_unix that binds almost every Unix system call. A higher-level module Lwt_io provides nice I/O channels.

  • Lwt_process is for subprocess handling.

  • Lwt_preemptive spawns system threads.

  • The PPX syntax allows using all of the above without going crazy!

  • There are also some other helpers, such as Lwt_react for reactive programming. See the table of contents on the linked manual pages!


Installing

  1. Use your system package manager to install a development libev package. It is often called libev-dev or libev-devel.

  2. opam install conf-libev lwt


Documentation

We are currently working on improving the Lwt documentation (drastically; we are rewriting the manual). In the meantime:

  • The current manual can be found here.

  • Mirage has a nicely-written Lwt tutorial.

  • An example of a simple server written in Lwt.

  • Concurrent Programming with Lwt is a nice source of Lwt examples. They are translations of code from the excellent Real World OCaml, but are just as useful if you are not reading the book.

Note: much of the current manual refers to 'a Lwt.t as "lightweight threads" or just "threads." This will be fixed in the new manual. 'a Lwt.t is a promise, and has nothing to do with system or preemptive threads.


Contact

Open an issue, visit Discord chat, ask on discuss.ocaml.org, or on Stack Overflow.

Release announcements are made in /r/ocaml, and on discuss.ocaml.org. Watching the repo for "Releases only" is also an option.


Contributing

  • CONTRIBUTING.md contains tips for working on the code, such as how to check the code out, how review works, etc. There is also a high-level outline of the code base.

  • Ask us anything, whether it's about working on Lwt, or any question at all about it :)

  • The documentation always needs proofreading and fixes.

  • You are welcome to pick up any other issue, review a PR, add your opinion, etc.

  • Any feedback is welcome, including how to make contributing easier!


Libraries to use with Lwt

Dependencies (5)

  1. ocplib-endian
  2. ocaml >= "4.08"
  3. dune-configurator
  4. dune >= "1.8.0"
  5. cppo build & >= "1.1.0"

Dev Dependencies (1)

  1. ocamlfind dev & >= "1.7.3-1"

  1. 0install >= "2.15.1"
  2. aches-lwt
  3. albatross
  4. alcotest-lwt
  5. alcotest-mirage
  6. ambient-context-lwt
  7. amqp-client >= "0.9.0" & < "1.0.2" | >= "1.1.0"
  8. amqp-client-lwt >= "2.0.1"
  9. angstrom-lwt-unix >= "0.11.0"
  10. anthill
  11. anycache-lwt
  12. arakoon < "1.8.6" | >= "1.8.8"
  13. archi-lwt
  14. arp >= "2.3.1"
  15. arp-mirage >= "2.2.1"
  16. awa-lwt
  17. awa-mirage
  18. aws-lwt
  19. aws-s3-lwt < "4.4.0"
  20. awsm-lwt
  21. azure-cosmos-db
  22. baardskeerder
  23. balancer
  24. bap < "1.0.0"
  25. bap-server < "0.2.0"
  26. bastet_lwt
  27. bimage-lwt
  28. biocaml = "0.4.0"
  29. bistro >= "0.4.0"
  30. brozip
  31. builder
  32. builder-web
  33. bun >= "0.3.3"
  34. c3
  35. calculon
  36. caldav
  37. camltc = "0.9.5" | >= "0.9.7.0"
  38. canary
  39. capnp-rpc-lwt
  40. capnp-rpc-unix >= "0.9.0"
  41. caqti-lwt >= "0.11.0"
  42. caqti-mirage
  43. carton
  44. carton-git
  45. carton-lwt
  46. cf-lwt
  47. chamelon
  48. chamelon-unix
  49. chamo >= "3.0"
  50. channel
  51. charrua-client >= "1.3.0"
  52. charrua-client-lwt
  53. charrua-client-mirage
  54. charrua-core < "0.3"
  55. charrua-unix >= "0.3" & != "0.10"
  56. clz
  57. cmdtui-lambda-term
  58. coclobas
  59. cohttp-curl-lwt
  60. cohttp-lwt
  61. cohttp-lwt-jsoo
  62. cohttp-lwt-unix >= "1.1.1"
  63. cohttp-lwt-unix-nossl
  64. cohttp-lwt-unix-ssl
  65. cohttp-mirage
  66. cohttp-server-lwt-unix
  67. comby
  68. comby-semantic
  69. conan-lwt
  70. conduit-lwt
  71. conduit-lwt-unix
  72. cowabloga >= "0.2.2"
  73. crunch >= "2.0.0"
  74. cstruct-lwt
  75. csv-lwt
  76. csvprovider
  77. ctypes >= "0.15.0" & < "0.21.1"
  78. ctypes-foreign >= "0.21.1"
  79. current
  80. current-albatross-deployer
  81. current_docker
  82. current_examples
  83. current_git
  84. current_github
  85. current_gitlab
  86. current_ocluster
  87. current_rpc >= "0.4"
  88. current_slack
  89. current_web
  90. DkSDKFFIOCaml_Std
  91. dap
  92. data-encoding < "0.1.1"
  93. datakit
  94. datakit-bridge-github
  95. datakit-bridge-local-git
  96. datakit-ci
  97. datakit-client = "0.11.0"
  98. datakit-github
  99. devkit >= "1.2"
  100. dht < "0.2.0"
  101. distributed-lwt
  102. dkim-mirage
  103. dlm
  104. dns >= "0.19.1" & < "0.20.1"
  105. dns-certify
  106. dns-cli >= "4.6.3"
  107. dns-client < "7.0.0"
  108. dns-client-lwt
  109. dns-client-mirage
  110. dns-forward >= "0.9.0"
  111. dns-forward-lwt-unix
  112. dns-lwt
  113. dns-mirage
  114. dns-resolver
  115. dns-server
  116. dns-stub
  117. dnssd
  118. docker_hub
  119. docteur >= "0.0.2"
  120. docteur-solo5
  121. docteur-unix >= "0.0.5"
  122. doi2bib
  123. dream
  124. dream-httpaf
  125. dream-pure
  126. dream-serve
  127. dropbox
  128. dune-rpc-lwt >= "3.7.0" & != "3.10.0"
  129. dune_watch
  130. earlybird
  131. elasticsearch-cli >= "0.4"
  132. equinoxe
  133. eris-lwt
  134. ethernet
  135. ez_api >= "1.2.0"
  136. ezcurl-lwt
  137. ezirmin
  138. ezjs_min < "0.2"
  139. ezjsonm >= "0.4.2" & < "0.5.0"
  140. ezjsonm-lwt
  141. ezresto
  142. ezresto-directory >= "0.5"
  143. faraday-lwt
  144. faraday-lwt-unix >= "0.6.0"
  145. fat-filesystem >= "0.12.0"
  146. fiber-lwt
  147. flowtype >= "0.72.0"
  148. frenetic < "2.0.0"
  149. fsevents-lwt
  150. fswatch_lwt
  151. fuseau-lwt
  152. gamepad
  153. gdb
  154. gdbprofiler >= "0.3"
  155. git != "1.4.3" & != "1.7.2"
  156. git-cohttp
  157. git-cohttp-mirage
  158. git-cohttp-unix
  159. git-mirage >= "3.0.0"
  160. git-paf
  161. git-unix = "1.11.1" | >= "3.0.0"
  162. github
  163. github-hooks < "0.2.0" | >= "0.4.0"
  164. github-unix >= "4.4.0"
  165. gitlab-unix
  166. gitlab_pipeline_notifier
  167. gluten-lwt
  168. gluten-lwt-unix < "0.4.0"
  169. gluten-mirage < "0.4.0"
  170. graphql-lwt
  171. gremlin
  172. grpc-lwt
  173. guardian
  174. gufo
  175. h2-lwt
  176. h2-lwt-unix < "0.10.0"
  177. h2-mirage
  178. happy-eyeballs-lwt
  179. happy-eyeballs-mirage
  180. hardcaml < "1.1.0"
  181. hardcaml-examples >= "0.3.0"
  182. hardcaml-framework
  183. hidapi-lwt
  184. hiredis != "0.4"
  185. hockmd
  186. horned_worm < "0.3.1"
  187. http-lwt-client
  188. http-mirage-client
  189. http-multipart-formdata >= "2.0.0" & < "3.0.0"
  190. http2https
  191. httpaf-lwt-unix
  192. hvsock >= "1.0.2"
  193. i3ipc >= "0.1.4"
  194. imaplet-lwt
  195. influxdb-lwt
  196. inotify >= "2.4"
  197. inquire < "0.3.0"
  198. interface-prime-lwt
  199. iocaml < "0.4.6"
  200. iocaml-kernel >= "0.4.3" & < "0.4.6"
  201. iocamljs-kernel
  202. ip2location
  203. ip2locationio
  204. ipv6-multicast-lwt
  205. irc-client-lwt
  206. irc-client-lwt-ssl
  207. irc-client-tls
  208. irmin < "0.9.6" | = "0.9.10" | >= "0.11.0"
  209. irmin-bench
  210. irmin-chunk
  211. irmin-cli
  212. irmin-client
  213. irmin-containers
  214. irmin-fs >= "2.3.0"
  215. irmin-git >= "2.3.0"
  216. irmin-graphql >= "2.3.0"
  217. irmin-http >= "2.3.0"
  218. irmin-indexeddb
  219. irmin-layers
  220. irmin-mem >= "2.3.0"
  221. irmin-mirage-git >= "2.3.0"
  222. irmin-mirage-graphql >= "2.3.0"
  223. irmin-pack
  224. irmin-server
  225. irmin-test >= "2.3.0"
  226. irmin-unix >= "2.3.0"
  227. irmin-watcher >= "0.3.0"
  228. jerboa
  229. jitsu
  230. joolog
  231. jose < "0.9.0"
  232. js_of_ocaml < "2.5"
  233. js_of_ocaml-lwt >= "3.5.0"
  234. jsoo_broadcastchannel
  235. jsoo_router
  236. jsoo_storage
  237. jupyter >= "2.3.0"
  238. jupyter-kernel >= "0.4"
  239. kafka >= "0.3" & < "0.5"
  240. kafka_lwt
  241. kappa-library
  242. ke >= "0.5"
  243. ketrew >= "3.2.0"
  244. kinetic-client < "0.0.3" | >= "0.0.9"
  245. kubecaml
  246. lablqml < "0.6"
  247. lambda-runtime
  248. lambda-term >= "1.13"
  249. lambda_streams_lwt
  250. launchd
  251. ldp
  252. learn-ocaml >= "0.13.0"
  253. learn-ocaml-client >= "0.13.0"
  254. ledgerwallet >= "0.4.0"
  255. letsencrypt
  256. letsencrypt-app
  257. letsencrypt-dns
  258. letters
  259. libres3
  260. links != "0.9"
  261. linol-lwt
  262. llama
  263. lru_cache < "v0.16.0"
  264. lwt-binio < "0.2.0"
  265. lwt-canceler
  266. lwt-dllist
  267. lwt-exit
  268. lwt-parallel >= "1.0.0"
  269. lwt-pipe
  270. lwt-pipeline
  271. lwt-watcher
  272. lwt-zmq < "1.0.0"
  273. lwt_camlp4
  274. lwt_domain
  275. lwt_eio
  276. lwt_glib >= "1.0.1"
  277. lwt_log >= "1.1.0"
  278. lwt_ppx
  279. lwt_ppx_let
  280. lwt_react >= "1.0.1"
  281. lwt_ssl >= "1.0.1"
  282. mariadb < "0.5.1"
  283. markup = "0.7.6"
  284. markup-lwt
  285. mdx
  286. mechaml
  287. mehari-lwt-unix
  288. mehari-mirage
  289. memtrace-mirage
  290. metrics-influx
  291. metrics-lwt
  292. metrics-mirage
  293. metrics-unix
  294. mimic
  295. mindstorm-lwt
  296. mirage >= "0.4.1" & != "0.6.1" & < "0.8.0" | >= "0.10.0" & < "2.7.0"
  297. mirage-block < "1.0.0" | >= "2.0.0"
  298. mirage-block-ccm
  299. mirage-block-combinators
  300. mirage-block-lwt
  301. mirage-block-partition
  302. mirage-block-ramdisk
  303. mirage-block-solo5
  304. mirage-block-unix < "2.3.0" | = "2.8.2" | >= "2.13.0"
  305. mirage-block-xen
  306. mirage-bootvar-solo5 >= "0.2.0"
  307. mirage-bootvar-unix
  308. mirage-bootvar-xen >= "0.4.0"
  309. mirage-channel >= "4.0.0"
  310. mirage-channel-lwt
  311. mirage-clock-freestanding < "3.0.0"
  312. mirage-clock-lwt
  313. mirage-clock-unix >= "1.3.0" & < "3.0.0"
  314. mirage-console >= "3.0.0"
  315. mirage-console-lwt
  316. mirage-console-solo5 >= "0.2.0"
  317. mirage-console-unix >= "2.2.1"
  318. mirage-console-xen >= "5.0.0"
  319. mirage-console-xen-backend
  320. mirage-console-xen-cli
  321. mirage-crypto-entropy
  322. mirage-crypto-rng >= "0.7.0" & < "0.11.0"
  323. mirage-crypto-rng-lwt
  324. mirage-crypto-rng-mirage >= "0.8.8"
  325. mirage-device >= "2.0.0"
  326. mirage-dns < "3.0.0"
  327. mirage-entropy
  328. mirage-flow >= "1.0.3" & < "1.2.0" | >= "2.0.0"
  329. mirage-flow-combinators
  330. mirage-flow-lwt < "1.3.0" | >= "1.5.0"
  331. mirage-flow-rawlink
  332. mirage-flow-unix >= "1.3.0"
  333. mirage-fs >= "3.0.0"
  334. mirage-fs-lwt
  335. mirage-fs-unix < "1.1.1" | >= "1.3.0"
  336. mirage-http
  337. mirage-http-unix
  338. mirage-http-xen
  339. mirage-kv >= "3.0.0"
  340. mirage-kv-lwt
  341. mirage-kv-unix
  342. mirage-logs != "0.3.0"
  343. mirage-nat < "3.0.0"
  344. mirage-net >= "3.0.1"
  345. mirage-net-fd
  346. mirage-net-lwt
  347. mirage-net-macosx
  348. mirage-net-solo5
  349. mirage-net-unix >= "2.2.0"
  350. mirage-net-xen
  351. mirage-os-shim >= "3.0.0"
  352. mirage-profile
  353. mirage-protocols >= "4.0.0" & < "8.0.0"
  354. mirage-protocols-lwt
  355. mirage-qubes < "0.2" | >= "0.4"
  356. mirage-qubes-ipv4
  357. mirage-random-stdlib >= "0.1.0"
  358. mirage-runtime >= "3.7.0"
  359. mirage-solo5
  360. mirage-stack >= "2.0.0" & < "4.0.0"
  361. mirage-stack-lwt
  362. mirage-time >= "2.0.0"
  363. mirage-time-lwt
  364. mirage-time-unix
  365. mirage-types-lwt < "3.7.1"
  366. mirage-unix >= "3.0.0"
  367. mirage-vnetif
  368. mirage-vnetif-stack
  369. mirage-www >= "1.1.0"
  370. mirage-xen
  371. mirror
  372. monorobot
  373. mqtt >= "0.0.2"
  374. mrmime >= "0.5.0"
  375. multipart-form-data >= "0.2.0"
  376. multipart_form >= "0.2.0" & < "0.4.0"
  377. multipart_form-cohttp-lwt
  378. multipart_form-lwt
  379. mwt
  380. naboris
  381. nanomsg
  382. nbd = "2.1.1" | >= "4.0.3"
  383. nbd-tool
  384. nbd-unix
  385. netchannel
  386. nocrypto >= "0.5.4"
  387. nottui-lwt
  388. nproc
  389. nsq >= "0.4.0"
  390. obrowser
  391. obuilder
  392. obus >= "1.2.1"
  393. ocaml-variants >= "4.00.1+mirage-unix" & < "4.00.1+open-types"
  394. ocluster
  395. ocluster-api
  396. ocluster-worker
  397. ocplib-concur
  398. ocplib-resto
  399. ocsigenserver >= "2.10"
  400. ocsipersist
  401. ocsipersist-dbm
  402. ocsipersist-lib
  403. ocsipersist-pgsql
  404. ocsipersist-sqlite
  405. octez-distributed-lwt-internal
  406. octez-l2-libs
  407. octez-libs
  408. octez-proto-libs
  409. octez-protocol-compiler
  410. octez-proxy-server
  411. octez-rpc-process
  412. octez-shell-libs
  413. octez-smart-rollup-wasm-benchmark-lib
  414. odoc >= "2.0.0" & < "2.1.0"
  415. oframl
  416. ojquery
  417. ojs-base
  418. ojs_base
  419. omigrate
  420. oneffs
  421. opam-sync-github-prs
  422. openflow < "0.2.0"
  423. opentelemetry-client-cohttp-lwt
  424. opentelemetry-cohttp-lwt >= "0.4"
  425. opentelemetry-lwt
  426. opium >= "0.11.0" & != "0.16.0"
  427. opium-graphql
  428. opium_kernel
  429. opomodoro
  430. order-i3-xfce
  431. ordma >= "0.0.3"
  432. oskel >= "0.3.0"
  433. ounit-lwt < "2.2.0"
  434. ounit2-lwt
  435. owork
  436. ox < "1.1.0"
  437. ozulip
  438. paf
  439. paf-cohttp
  440. pcap-format >= "0.3.3" & < "0.5.0"
  441. petrol
  442. pgx_lwt
  443. pgx_lwt_mirage
  444. pgx_lwt_unix < "2.0"
  445. piaf
  446. plebeia >= "2.0.0"
  447. plist-xml-lwt
  448. plotkicadsch >= "0.4.0"
  449. ppx_defer >= "0.4.0"
  450. ppx_deriving_rpc
  451. ppx_json_types
  452. ppx_netblob
  453. ppx_rapper_lwt
  454. ppx_sqlexpr
  455. proc-smaps
  456. prof_spacetime
  457. prometheus
  458. prometheus-app
  459. protocol-9p >= "0.10.0"
  460. protocol-9p-unix
  461. qcow >= "0.8.1"
  462. qcow-format < "0.3"
  463. qcow-tool
  464. qfs = "0.5" | >= "0.7"
  465. quests
  466. rawlink >= "1.0" & < "2.1"
  467. rawlink-lwt
  468. rdf_json_ld
  469. rdf_lwt
  470. redis-lwt
  471. reparse-lwt
  472. reparse-lwt-unix
  473. resource-pooling >= "0.3.2"
  474. resp
  475. resp-mirage >= "0.10.0"
  476. resp-unix >= "0.10.0"
  477. resto
  478. resto-cohttp-client >= "0.4"
  479. resto-cohttp-self-serving-client
  480. resto-cohttp-server >= "0.4" & < "0.6" | >= "0.9"
  481. resto-directory >= "0.4"
  482. riak
  483. ringo-lwt
  484. river
  485. rock
  486. rpc >= "1.5.1" & < "7.1.0"
  487. rpclib-js
  488. rpclib-lwt
  489. SZXX < "4.0.0"
  490. sanddb
  491. scgi
  492. sendmail-lwt
  493. serial
  494. server-reason-react
  495. session-cohttp-lwt
  496. session-cookie-lwt
  497. session-postgresql-lwt >= "0.4.1"
  498. sessions
  499. shared-block-ring < "2.3.0" | >= "3.0.0"
  500. shared-memory-ring >= "1.2.0" & < "2.0.0"
  501. shared-memory-ring-lwt
  502. sherlodoc
  503. sihl < "0.2.0"
  504. slacko
  505. socket-daemon < "0.3.0"
  506. spin < "0.8.0"
  507. spoke
  508. spotify-web-api < "0.2.1"
  509. sqlexpr = "0.7.1" | >= "0.9.0"
  510. statsd-client
  511. stk
  512. stog >= "0.16.0"
  513. syguslib-utils
  514. syndic >= "1.4" & < "1.6.0"
  515. tar-format >= "0.4.1"
  516. tar-mirage
  517. tar-unix
  518. tcpip >= "3.1.1" & < "3.4.1" | >= "4.1.0"
  519. teash
  520. telegraml
  521. terminus
  522. tezos-base >= "13.0"
  523. tezos-clic >= "13.0"
  524. tezos-crypto >= "13.0"
  525. tezos-crypto-dal
  526. tezos-error-monad >= "8.0" & < "9.0" | >= "13.0"
  527. tezos-lwt-result-stdlib >= "9.0"
  528. tezos-p2p >= "11.0" & < "13.0"
  529. tezos-protocol-compiler >= "13.0"
  530. tezos-protocol-environment >= "13.0"
  531. tezos-proxy >= "17.1"
  532. tezos-proxy-server
  533. tezos-stdlib
  534. tezos-stdlib-unix >= "8.0" & < "9.0" | >= "13.0"
  535. tezos-test-helpers >= "12.0"
  536. tezos-wasmer
  537. tezos-webassembly-interpreter-extra
  538. tezt
  539. tftp
  540. themoviedb
  541. tidy_email
  542. tls = "0.10.1" | >= "0.10.6" & < "0.16.0"
  543. tls-lwt
  544. tls-mirage
  545. transmission-rpc
  546. tube >= "4.3.0"
  547. tuntap >= "1.0.0" & < "1.7.0" | >= "2.0.0"
  548. typerex-lldb
  549. u2f
  550. uring
  551. uspf
  552. uspf-lwt
  553. utop >= "1.4.0"
  554. uwt >= "0.3.0"
  555. vchan >= "0.9.7" & < "2.0.0" | >= "2.0.3"
  556. vchan-unix
  557. vchan-xen
  558. vercel
  559. vhd-format >= "0.7.0" & < "0.8.0"
  560. vhd-format-lwt >= "0.12.0"
  561. vhd-tool < "0.12.0"
  562. vmnet >= "1.3.2"
  563. vpnkit >= "0.2.0"
  564. vue-jsoo < "0.3"
  565. wayland < "2.0"
  566. webauthn
  567. websocket < "2.3"
  568. xe-unikernel-upload
  569. xen-api-client < "0.9.14"
  570. xen-block-driver
  571. xen-evtchn < "1.0.6" | >= "2.0.0"
  572. xen-evtchn-unix
  573. xen-gnt >= "2.2.3"
  574. xenctrl < "0.9.29" | >= "0.9.32"
  575. xenstore >= "1.3.0"
  576. xenstore_transport >= "1.0.0"
  577. xentropyd
  578. yocaml_git
  579. yocaml_unix
  580. yurt < "0.3"
  581. zmq-lwt >= "5.2.1"

Conflicts

None