[Caml-list] Attn: Development Editor, Latest OCaml Weekly News

[Alan Schmitt <alan.schmitt@polytechnique.org>]

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Hello

Here is the latest OCaml Weekly News, for the week of November 05 to 12,
2024.

Table of Contents
─────────────────

Picos — Interoperable effects based concurrency
findlib-1.9.7
First release candidate for OCaml 5.2.1
mirage-swapfs
Dune dev meeting
Other OCaml News
Old CWN


Picos — Interoperable effects based concurrency
═══════════════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/ann-picos-interoperable-effects-based-concurrency/14507/3>


polytypic announced
───────────────────

  I'm happy to announce that Picos version 0.6.0 has been released!

        Picos is a systems programming interface between effects
        based schedulers and concurrent abstractions.

  A lot of work has been done on Picos since previous announcements.

  You might start on the new minimalist landing page for [Picos], which,
  among other things, allows you to access the documentation of all the
  released Picos versions.

  Also, in case you missed it, a recording of the talk

        [Picos — Interoperable effects based concurrency]

  can be found [here].

  We also held a workshop on concurrency and parallelism at [Fun
  OCaml]. You might enjoy trying out [the exercise we developed for the
  workshop].

  As, for reasons of dependencies, Picos now comes in no less than [8
  packages] and multiple libraries, here is a summary of the packages
  and the libraries inside each package:

  • [`picos'] — Picos — Interoperable effects based concurrency
    • [`picos'] — A systems programming interface between effects based
      schedulers and concurrent abstractions
    • [`picos.domain'] — Minimalistic domain API available both on OCaml
      5 and on OCaml 4
    • [`picos.thread'] — Minimalistic thread API available with or
      without threads.posix

  • [`picos_mux'] — Sample schedulers for Picos
    • [`picos_mux.fifo'] — Basic single-threaded effects based Picos
      compatible scheduler for OCaml 5
    • [`picos_mux.multififo'] — Basic multi-threaded effects based Picos
      compatible scheduler for OCaml 5
    • [`picos_mux.random'] — Randomized multi-threaded effects based
      Picos compatible scheduler for OCaml 5
    • [`picos_mux.thread'] — Basic Thread based Picos compatible
      scheduler for OCaml 4

  • [`picos_std'] — Sample libraries for Picos
    • [`picos_std.finally'] — Syntax for avoiding resource leaks for
      Picos
    • [`picos_std.awaitable'] — Basic futex-like awaitable atomic
      location for Picos
    • [`picos_std.event'] — Basic event abstraction for Picos
    • [`picos_std.structured'] — Basic structured concurrency primitives
      for Picos
    • [`picos_std.sync'] — Basic communication and synchronization
      primitives for Picos

  • [`picos_io'] — Asynchronous IO system for Picos
    • [`picos_io'] — Basic IO facilities based on OCaml standard
      libraries for Picos
    • [`picos_io.select'] — Basic Unix.select based IO event loop for
      Picos
    • [`picos_io.fd'] — Externally reference counted file descriptors

  • [`picos_io_cohttp'] — Cohttp running on Picos IO
    • [`picos_io_cohttp'] — Minimalistic Cohttp implementation using
      Picos_io for Picos

  • [`picos_lwt'] — Lwt interface for Picos
    • [`picos_lwt'] — Direct style Picos compatible interface to Lwt for
      OCaml 5
    • [`picos_lwt.unix'] — Direct style Picos compatible interface to
      Lwt with Lwt_unix for OCaml 5

  • [`picos_aux'] — Auxiliary libraries for Picos
    • [`picos_aux.htbl'] — Lock-free hash table
    • [`picos_aux.mpmcq'] — Lock-free multi-producer, multi-consumer
      queue
    • [`picos_aux.mpscq'] — Lock-free multi-producer, single-consumer
      queue
    • [`picos_aux.rc'] — External reference counting tables for
      disposable resources

  • [`picos_meta'] — Integration tests for Picos packages

  In addition to the above, [Moonpool] now uses Picos underneath.

  And, I almost forgot, there is a ready to be merged [PR for Kcas to
  change it to use Picos].  You should be able to try it with an opam
  [pin-depends].


[Picos] <https://ocaml-multicore.github.io/picos/>

[Picos — Interoperable effects based concurrency]
<https://icfp24.sigplan.org/details/ocaml-2024-papers/5/Picos-Interoperable-effects-based-concurrency>

[here] <https://youtu.be/OuQqblCxJ2Y?t=20115>

[Fun OCaml] <https://fun-ocaml.com/>

[the exercise we developed for the workshop]
<https://github.com/ocaml-multicore/fun-ocaml-workshop>

[8 packages] <https://ocaml-multicore.github.io/picos/0.6.0/>

[`picos']
<https://ocaml-multicore.github.io/picos/0.6.0/picos/index.html>

[`picos']
<https://ocaml-multicore.github.io/picos/0.6.0/picos/Picos/index.html>

[`picos.domain']
<https://ocaml-multicore.github.io/picos/0.6.0/picos/Picos_domain/index.html>

[`picos.thread']
<https://ocaml-multicore.github.io/picos/0.6.0/picos/Picos_thread/index.html>

[`picos_mux']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_mux/index.html>

[`picos_mux.fifo']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_mux/Picos_mux_fifo/index.html>

[`picos_mux.multififo']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_mux/Picos_mux_multififo/index.html>

[`picos_mux.random']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_mux/Picos_mux_random/index.html>

[`picos_mux.thread']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_mux/Picos_mux_thread/index.html>

[`picos_std']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_std/index.html>

[`picos_std.finally']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_std/Picos_std_finally/index.html>

[`picos_std.awaitable']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_std/Picos_std_awaitable/index.html>

[`picos_std.event']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_std/Picos_std_event/index.html>

[`picos_std.structured']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_std/Picos_std_structured/index.html>

[`picos_std.sync']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_std/Picos_std_sync/index.html>

[`picos_io']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_io/index.html>

[`picos_io']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_io/Picos_io/index.html>

[`picos_io.select']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_io/Picos_io_select/index.html>

[`picos_io.fd']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_io/Picos_io_fd/index.html>

[`picos_io_cohttp']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_io_cohttp/index.html>

[`picos_io_cohttp']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_io_cohttp/Picos_io_cohttp/index.html>

[`picos_lwt']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_lwt/index.html>

[`picos_lwt']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_lwt/Picos_lwt/index.html>

[`picos_lwt.unix']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_lwt/Picos_lwt_unix/index.html>

[`picos_aux']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_aux/index.html>

[`picos_aux.htbl']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_aux/Picos_aux_htbl/index.html>

[`picos_aux.mpmcq']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_aux/Picos_aux_mpmcq/index.html>

[`picos_aux.mpscq']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_aux/Picos_aux_mpscq/index.html>

[`picos_aux.rc']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_aux/Picos_aux_rc/index.html>

[`picos_meta']
<https://ocaml-multicore.github.io/picos/0.6.0/picos_meta/index.html>

[Moonpool] <https://github.com/c-cube/moonpool>

[PR for Kcas to change it to use Picos]
<https://github.com/ocaml-multicore/kcas/pull/204>

[pin-depends]
<https://opam.ocaml.org/doc/Manual.html#opamfield-pin-depends>


findlib-1.9.7
═════════════

  Archive:
  <https://sympa.inria.fr/sympa/arc/caml-list/2024-11/msg00004.html>


Gerd Stolpmann announced
────────────────────────

  findlib-1.9.7 is out. This is mostly a bugfix release. There is now
  also some support for relocability (driven by environment variables),
  contributed by Marek Kubica.

  For manual, download, manuals, etc. see here:

  <http://projects.camlcity.org/projects/findlib.html>

  An updated OPAM package will follow soon.


First release candidate for OCaml 5.2.1
═══════════════════════════════════════

  Archive:
  <https://discuss.ocaml.org/t/first-release-candidate-for-ocaml-5-2-1/15578/1>


octachron announced
───────────────────

  The release of OCaml version 5.2.1 is imminent.

  OCaml 5.2.1 is a collection of safe but import runtime time bug fixes
  backported from the 5.3 branch of OCaml. The full list of bug fixes is
  available below.

  In order to ensure that the future release works as expected, we are
  planning to test a release candidate during the upcoming week.

  If you find any bugs, please report them here on [GitHub].


[GitHub] <https://github.com/ocaml/ocaml/issues>

Installation Instructions
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The base compiler can be installed as an opam switch with the
  following commands on opam 2.1:
  ┌────
  │ opam update
  │ opam switch create 5.2.1~rc1
  └────

  The source code for the release candidate is available on

  • [GitHub]
  • [Inria archives]


[GitHub] <https://github.com/ocaml/ocaml/archive/5.2.1-rc1.tar.gz>

[Inria archives]
<https://caml.inria.fr/pub/distrib/ocaml-5.2/ocaml-5.2.1~rc1.tar.gz>

◊ Fine-Tuned Compiler Configuration

  If you want to tweak the configuration of the compiler, you can switch
  to the option variant with:
  ┌────
  │ opam update
  │ opam switch create <switch_name> ocaml-variants.5.2.1~rc1+options <option_list>
  └────
  where `<option_list>` is a space-separated list of `ocaml-option-*`
  packages. For instance, for a `flambda` and `no-flat-float-array`
  switch:
  ┌────
  │ opam switch create 5.2.1~rc1+flambda+nffa ocaml-variants.5.2.1~rc1+options ocaml-option-flambda ocaml-option-no-flat-float-array
  └────

  All available options can be listed with `opam search ocaml-option`.

  *Changes Since OCaml 5.2.0*


Runtime System:
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • [#13207]: Be sure to reload the register caching the exception
    handler in caml_c_call and caml_c_call_stack_args, as its value may
    have been changed if the OCaml stack is expanded during a callback.
    (Miod Vallat, report by Vesa Karvonen, review by Gabriel Scherer and
    Xavier Leroy)
  • [#13252]: Rework register assignment in the interpreter code on m68k
    on Linux, due to the %a5 register being used by Glibc.  (Miod
    Vallat, report by Stéphane Glondu, review by Gabriel Scherer and
    Xavier Leroy)
  • [#13268]: Fix a call to test in configure.ac that was causing errors
    when LDFLAGS contains several words.  (Stéphane Glondu, review by
    Miod Vallat)
  • [#13234], [#13267]: Open runtime events file in read-write mode on
    armel (armv5) systems due to atomic operations limitations on that
    platform.  (Stéphane Glondu, review by Miod Vallat and Vincent
    Laviron)
  • [#13188]: fix races in the FFI code coming from the use of
    Int_val(…)  on rooted values inside blocking questions / without the
    runtime lock.  (Calling Int_val(…) on non-rooted immediates is fine,
    but any access to rooted values must be done outside blocking
    sections / with the runtime lock.)  (Etienne Millon, review by
    Gabriel Scherer, Jan Midtgaard, Olivier Nicole)
  • [#13318]: Fix regression in GC alarms, and fix them for flambda.
    (Guillaume Munch-Maccagnoni, report by Benjamin Monate, review by
    Vincent Laviron and Gabriel Scherer)
  • [#13140]: POWER back-end: fix issue with call to
    `caml_call_realloc_stack` from a DLL (Xavier Leroy, review by Miod
    Vallat)
  • [#13370]: Fix a low-probability crash when calling Gc.counters.
    (Demi Marie Obenour, review by Gabriel Scherer)
  • [#13402], [#13512], [#13549], [#13553]: Revise bytecode
    implementation of callbacks so that it no longer produces dangling
    registered bytecode fragments.  (Xavier Leroy, report by Jan
    Midtgaard, analysis by Stephen Dolan, review by Miod Vallat)
  • [#13502]: Fix misindexing related to `Gc.finalise_last` that could
    prevent finalisers from being run.  (Nick Roberts, review by Mark
    Shinwell)
  • [#13520]: Fix compilation of native-code version of
    systhreads. Bytecode fields were being included in the thread
    descriptors.  (David Allsopp, review by Sébastien Hinderer and Miod
    Vallat)


[#13207] <https://github.com/ocaml/ocaml/issues/13207>

[#13252] <https://github.com/ocaml/ocaml/issues/13252>

[#13268] <https://github.com/ocaml/ocaml/issues/13268>

[#13234] <https://github.com/ocaml/ocaml/issues/13234>

[#13267] <https://github.com/ocaml/ocaml/issues/13267>

[#13188] <https://github.com/ocaml/ocaml/issues/13188>

[#13318] <https://github.com/ocaml/ocaml/issues/13318>

[#13140] <https://github.com/ocaml/ocaml/issues/13140>

[#13370] <https://github.com/ocaml/ocaml/issues/13370>

[#13402] <https://github.com/ocaml/ocaml/issues/13402>

[#13512] <https://github.com/ocaml/ocaml/issues/13512>

[#13549] <https://github.com/ocaml/ocaml/issues/13549>

[#13553] <https://github.com/ocaml/ocaml/issues/13553>

[#13502] <https://github.com/ocaml/ocaml/issues/13502>

[#13520] <https://github.com/ocaml/ocaml/issues/13520>


mirage-swapfs
═════════════

  Archive: <https://discuss.ocaml.org/t/ann-mirage-swapfs/15583/1>


Reynir Björnsson announced
──────────────────────────

  I am pleased to announce the first release of [mirage-swapfs] (swapfs
  on opam). It is an experimental library to use a mirage block device
  for ephemeral, append-only, anonymous "files". It was developed for
  use cases such as in [opam-mirror] where opam package source archives
  are downloaded. The files are first downloaded to "swap" and if the
  download succeeds and the checksum is as expected the data is then
  copied over to the tar filesystem.

  Internally it uses a weak pointer array (`Weak.t') to map "block"
  offsets to handles. The idea is the garbage collector can help us free
  up "blocks" if the user forgets to explicitly free the handle. A
  "block" is (configurable, see `blocking_factor') multiple of sectors
  in order to reduce bookkeeping overhead. With a sector size of 512
  bytes the default is 1 MiB per block.

  See also the documentation
  <https://robur-coop.github.io/mirage-swapfs/doc/swapfs/index.html>

  I would be interested to hear about other ideas or approaches.


[mirage-swapfs] <https://github.com/robur-coop/mirage-swapfs>

[opam-mirror] <https://git.robur.coop/robur/opam-mirror/>


Dune dev meeting
════════════════

  Archive: <https://discuss.ocaml.org/t/ann-dune-dev-meeting/14994/16>


Etienne Marais announced
────────────────────────

  We will hold our regular Dune dev meeting tomorrow, on Wednesday,
  November, 13th at *9:00* CET. :warning: Note that the session has been
  moved *one hour earlier*. As usual, the session will be one hour long.

  Whether you are a maintainer, a regular contributor, a new joiner or
  just curious, you are welcome to join: these discussions are opened!
  The goal of these meetings is to provide a place to discuss the
  ongoing work together and synchronise between the Dune developers
  !:smile:


:calendar: Agenda
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  The agenda is available on the [meeting dedicated page]. Feel free to
  ask if you want to add more items in it.


[meeting dedicated page]
<https://github.com/ocaml/dune/wiki/dev-meeting-2024-11-13>


:computer: Links
╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌

  • Meeting link:[ zoom]
  • Calendar event:[ google calendar]
  • Wiki with information and previous notes:[ GitHub Wiki]


[ zoom]
<https://us06web.zoom.us/j/85096877776?pwd=cWNhU1dHQ1ZNSjZuOUZCQ0h2by9Udz09>

[ google calendar]
<https://calendar.google.com/calendar/embed?src=c_5cd698df6784e385b1cdcdc1dbca18c061faa96959a04781566d304dc9ec7319%40group.calendar.google.com>

[ GitHub Wiki] <https://github.com/ocaml/dune/wiki#dev-meetings>


Other OCaml News
════════════════

>From the ocaml.org blog
───────────────────────

  Here are links from many OCaml blogs aggregated at [the ocaml.org
  blog].

  • [Beta release of Frama-C 30.0~beta (Zinc)]
  • [Making OCaml Mainstream: Support Our Open Source Work on GitHub]


[the ocaml.org blog] <https://ocaml.org/blog/>

[Beta release of Frama-C 30.0~beta (Zinc)]
<https://frama-c.com/fc-versions/zinc.html>

[Making OCaml Mainstream: Support Our Open Source Work on GitHub]
<https://tarides.com/blog/2024-11-06-making-ocaml-mainstream-support-our-open-source-work-on-github>


Old CWN
═══════

  If you happen to miss a CWN, you can [send me a message] and I'll mail
  it to you, or go take a look at [the archive] or the [RSS feed of the
  archives].

  If you also wish to receive it every week by mail, you may subscribe
  to the [caml-list].

  [Alan Schmitt]


[send me a message] <mailto:alan.schmitt@polytechnique.org>

[the archive] <https://alan.petitepomme.net/cwn/>

[RSS feed of the archives] <https://alan.petitepomme.net/cwn/cwn.rss>

[caml-list] <https://sympa.inria.fr/sympa/info/caml-list>

[Alan Schmitt] <https://alan.petitepomme.net/>


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