# OCaml 4.09.0 released **URL:** \ **Category:** Ecosystem\ **Created:** [September 19, 2019, 8:54am UTC](https://discuss.ocaml.org/t/ocaml-4-09-0-released/4384 "2019-09-19T08:54:47Z")\ **Posts on this page:** 1\ **Showing post:** 1
**Author:** ![octachron](https://avatars.discourse-cdn.com/v4/letter/o/49beb7/32.png) [@octachron](https://discuss.ocaml.org/u/octachron)\ **Post date:** [September 19, 2019, 8:54am UTC](https://discuss.ocaml.org/t/ocaml-4-09-0-released/4384/1 "2019-09-19T08:54:47Z")
The OCaml team have the pleasure of celebrating the birth of James Waddell Alexander II by announcing the release of OCaml version 4.09.0 . Some of the highlights of this new 4.09 release are: - New optimisations, in particular for affine functions in matches, for instance ```auto type t = A | B | C let affine = function | A -> 4 | B -> 3 | C -> 2 ``` - The `graphics` library was moved out of the compiler distribution. - The `vmthread` library was removed. - Support for compiler plugins was removed. - Many bug fixes. The full list of change can be found in the changelog below. It is available as a set of OPAM switches, and as a source download here: [https://caml.inria.fr/pub/distrib/ocaml-4.09/](https://caml.inria.fr/pub/distrib/ocaml-4.09/) Happy hacking. * * * ## Changes This is the [changelog](http://caml.inria.fr/pub/distrib/ocaml-4.09/notes/Changes) . ### Runtime system: - (_breaking change_) [#1725](https://github.com/ocaml/ocaml/issues/1725), [#2279](https://github.com/ocaml/ocaml/issues/2279): Deprecate Obj.set\_tag and Obj.truncate (Stephen Dolan, review by Gabriel Scherer, Damien Doligez and Xavier Leroy) - (_breaking change_) [#2240](https://github.com/ocaml/ocaml/issues/2240): Constify “identifier” in struct custom\_operations (Cedric Cellier, review by Xavier Leroy) - (_breaking change_) [#2293](https://github.com/ocaml/ocaml/issues/2293): Constify “caml\_named\_value” (Stephen Dolan, review by Xavier Leroy) - [#8787](https://github.com/ocaml/ocaml/issues/8787), [#8788](https://github.com/ocaml/ocaml/issues/8788): avoid integer overflow in caml\_output\_value\_to\_bytes (Jeremy Yallop, report by Marcello Seri) - [#2075](https://github.com/ocaml/ocaml/issues/2075), [#7729](https://github.com/ocaml/ocaml/issues/7729): rename \_T macro used to support Unicode in the (Windows) runtime in order to avoid compiler warning (Nicolás Ojeda Bär, review by Gabriel Scherer and David Allsopp) - [#2250](https://github.com/ocaml/ocaml/issues/2250): Remove extra integer sign-extension in compare functions (Stefan Muenzel, review by Xavier Leroy) - [#8607](https://github.com/ocaml/ocaml/issues/8607): Remove obsolete macros for pre-2002 MSVC support (Stephen Dolan, review by Nicolás Ojeda Bär and David Allsopp) - [#8656](https://github.com/ocaml/ocaml/issues/8656): Fix a bug in [caml\_modify\_generational\_global\_root] (Jacques-Henri Jourdan, review by Gabriel Scherer) ### Standard library: - [#2262](https://github.com/ocaml/ocaml/issues/2262): take precision (.) and flags (’+’ and ’ ') into account in printf %F (Pierre Roux, review by Gabriel Scherer) - [#6148](https://github.com/ocaml/ocaml/issues/6148), [#8596](https://github.com/ocaml/ocaml/issues/8596): optimize some buffer operations (Damien Doligez, reports by John Whitington and Alain Frisch, review by Jeremy Yallop and Gabriel Scherer) ### Other libraries: - (_breaking change_) [#2318](https://github.com/ocaml/ocaml/issues/2318): Delete the graphics library. This library is now available as a separate “graphics” package in opam. Its new home is: [https://github.com/ocaml/graphics](https://github.com/ocaml/graphics) (Jérémie Dimino, review by Nicolas Ojeda Bar, Xavier Leroy and Sébastien Hinderer) - (_breaking change_) [#2289](https://github.com/ocaml/ocaml/issues/2289): Delete the vmthreads library. This library was deprecated in 4.08.0. (Jérémie Dimino) - [#2112](https://github.com/ocaml/ocaml/issues/2112): Fix Thread.yield unfairness with busy threads yielding to each other. (Andrew Hunter, review by Jacques-Henri Jourdan, Spiros Eliopoulos, Stephen Weeks, & Mark Shinwell) - [#7903](https://github.com/ocaml/ocaml/issues/7903), [#2306](https://github.com/ocaml/ocaml/issues/2306): Make Thread.delay interruptible by signals again (Xavier Leroy, review by Jacques-Henri Jourdan and Edwin Török) - [#2248](https://github.com/ocaml/ocaml/issues/2248): Unix alloc\_sockaddr: Fix read of uninitialized memory for an unbound Unix socket. Add support for receiving abstract (Linux) socket paths. (Tim Cuthbertson, review by Sébastien Hinderer and Jérémie Dimino) ### Compiler user-interface and warnings: - (_breaking change_) [#2276](https://github.com/ocaml/ocaml/issues/2276): Remove support for compiler plugins and hooks (also adds [Dynlink.unsafe\_get\_global\_value]) (Mark Shinwell, Xavier Clerc, review by Nicolás Ojeda Bär, Florian Angeletti, David Allsopp and Xavier Leroy) - [#2301](https://github.com/ocaml/ocaml/issues/2301): Hint on type error on int literal (Jules Aguillon, review by Nicolás Ojeda Bär , Florian Angeletti, Gabriel Scherer and Armaël Guéneau) - (_breaking change_) [#2314](https://github.com/ocaml/ocaml/issues/2314): Remove support for gprof profiling. (Mark Shinwell, review by Xavier Clerc and Stephen Dolan) - [#2190](https://github.com/ocaml/ocaml/issues/2190): fix pretty printing (using Pprintast) of “lazy …” patterns and “fun (type t) -\> …” expressions. (Nicolás Ojeda Bär, review by Gabriel Scherer) - [#2277](https://github.com/ocaml/ocaml/issues/2277): Use newtype names as type variable names The inferred type of (fun (type t) (x : t) -\> x) is now printed as ('t -\> 't) rather than ('a -\> 'a). (Matthew Ryan) - [#2309](https://github.com/ocaml/ocaml/issues/2309): New options -with-runtime and -without-runtime in ocamlopt/ocamlc that control the inclusion of the runtime system in the generated program. (Lucas Pluvinage, review by Daniel Bünzli, Damien Doligez, David Allsopp and Florian Angeletti) - [#3819](https://github.com/ocaml/ocaml/issues/3819), [#8546](https://github.com/ocaml/ocaml/issues/8546) more explanations and tests for illegal permutation (Florian Angeletti, review by Gabriel Scherer) - [#8537](https://github.com/ocaml/ocaml/issues/8537): fix the -runtime-variant option for bytecode (Damien Doligez, review by David Allsopp) - [#8541](https://github.com/ocaml/ocaml/issues/8541): Correctly print multi-lines locations (Louis Roché, review by Gabriel Scherer) - [#8579](https://github.com/ocaml/ocaml/issues/8579): Better error message for private constructors of an extensible variant type (Guillaume Bury, review by many fine eyes) ### Code generation and optimizations: - [#2278](https://github.com/ocaml/ocaml/issues/2278): Remove native code generation support for 32-bit Intel macOS, iOS and other Darwin targets. (Mark Shinwell, review by Nicolas Ojeda Bar and Xavier Leroy) - [#8547](https://github.com/ocaml/ocaml/issues/8547): Optimize matches that are an affine function of the input. (Stefan Muenzel, review by Alain Frisch, Gabriel Scherer) - [#1904](https://github.com/ocaml/ocaml/issues/1904), [#7931](https://github.com/ocaml/ocaml/issues/7931): Add FreeBSD/aarch64 support (Greg V, review by Sébastien Hinderer, Stephen Dolan, Damien Doligez and Xavier Leroy) - [#8507](https://github.com/ocaml/ocaml/issues/8507): Shorten symbol names of anonymous functions in Flambda mode (the directory portions are now hidden) (Mark Shinwell, review by Nicolás Ojeda Bär) - [#8681](https://github.com/ocaml/ocaml/issues/8681), [#8699](https://github.com/ocaml/ocaml/issues/8699), [#8712](https://github.com/ocaml/ocaml/issues/8712): Fix code generation with nested let rec of functions. (Stephen Dolan, Leo White, Gabriel Scherer and Pierre Chambart, review by Gabriel Scherer, reports by Alexey Solovyev and Jonathan French) ### Manual and documentation: - [#7584](https://github.com/ocaml/ocaml/issues/7584), [#8538](https://github.com/ocaml/ocaml/issues/8538): Document .cmt\* files in the “overview” of ocaml{c,opt} (Oxana Kostikova, rewiew by Florian Angeletti) - [#8757](https://github.com/ocaml/ocaml/issues/8757): Rename Pervasives to Stdlib in core library documentation. (Ian Zimmerman, review by David Allsopp) - [#8515](https://github.com/ocaml/ocaml/issues/8515): manual, precise constraints on reexported types (Florian Angeletti, review by Gabriel Scherer) ### Tools: - [#2221](https://github.com/ocaml/ocaml/issues/2221): ocamldep will now correctly allow a .ml file in an include directory that appears first in the search order to shadow a .mli appearing in a later include directory. (Nicolás Ojeda Bär, review by Florian Angeletti) ### Internal/compiler-libs changes: - [#1579](https://github.com/ocaml/ocaml/issues/1579): Add a separate types for clambda primitives (Pierre Chambart, review by Vincent Laviron and Mark Shinwell) - [#1965](https://github.com/ocaml/ocaml/issues/1965): remove loop constructors in Cmm and Mach (Vincent Laviron) - [#1973](https://github.com/ocaml/ocaml/issues/1973): fix compilation of catches with multiple handlers (Vincent Laviron) - [#2228](https://github.com/ocaml/ocaml/issues/2228), [#8545](https://github.com/ocaml/ocaml/issues/8545): refactoring the handling of .cmi files by moving the logic from Env to a new module Persistent\_env (Gabriel Scherer, review by Jérémie Dimino and Thomas Refis) - [#2229](https://github.com/ocaml/ocaml/issues/2229): Env: remove prefix\_idents cache (Thomas Refis, review by Frédéric Bour and Gabriel Scherer) - [#2237](https://github.com/ocaml/ocaml/issues/2237), [#8582](https://github.com/ocaml/ocaml/issues/8582): Reorder linearisation of Trywith to avoid a call instruction (Vincent Laviron and Greta Yorsh, additional review by Mark Shinwell; fix in [#8582](https://github.com/ocaml/ocaml/issues/8582) by Mark Shinwell, Xavier Leroy and Anil Madhavapeddy) - [#2265](https://github.com/ocaml/ocaml/issues/2265): Add bytecomp/opcodes.mli (Mark Shinwell, review by Nicolas Ojeda Bar) - [#2268](https://github.com/ocaml/ocaml/issues/2268): Improve packing mechanism used for building compilerlibs modules into the Dynlink libraries (Mark Shinwell, Stephen Dolan, review by David Allsopp) - [#2280](https://github.com/ocaml/ocaml/issues/2280): Don’t make more Clambda constants after starting Cmmgen (Mark Shinwell, review by Vincent Laviron) - [#2281](https://github.com/ocaml/ocaml/issues/2281): Move some middle-end files around (Mark Shinwell, review by Pierre Chambart and Vincent Laviron) - [#2283](https://github.com/ocaml/ocaml/issues/2283): Add [is\_prefix] and [find\_and\_chop\_longest\_common\_prefix] to [Misc.Stdlib.List] (Mark Shinwell, review by Alain Frisch and Stephen Dolan) - [#2284](https://github.com/ocaml/ocaml/issues/2284): Add various utility functions to [Misc] and remove functions from [Misc.Stdlib.Option] that are now in [Stdlib.Option] (Mark Shinwell, review by Thomas Refis) - [#2286](https://github.com/ocaml/ocaml/issues/2286): Functorise [Consistbl] (Mark Shinwell, review by Gabriel Radanne) - [#2291](https://github.com/ocaml/ocaml/issues/2291): Add [Compute\_ranges] pass (Mark Shinwell, review by Vincent Laviron) - [#2292](https://github.com/ocaml/ocaml/issues/2292): Add [Proc.frame\_required] and [Proc.prologue\_required]. Move tail recursion label creation to [Linearize]. Correctly position [Lprologue] relative to [Iname\_for\_debugger] operations. (Mark Shinwell, review by Vincent Laviron) - [#2308](https://github.com/ocaml/ocaml/issues/2308): More debugging information on [Cmm] terms (Mark Shinwell, review by Stephen Dolan) - [#7878](https://github.com/ocaml/ocaml/issues/7878), [#8542](https://github.com/ocaml/ocaml/issues/8542): Replaced TypedtreeIter with tast\_iterator (Isaac “Izzy” Avram, review by Gabriel Scherer and Nicolás Ojeda Bär) - [#8598](https://github.com/ocaml/ocaml/issues/8598): Replace “not is\_nonexpansive” by “maybe\_expansive”. (Thomas Refis, review by David Allsopp, Florian Angeletti, Gabriel Radanne, Gabriel Scherer and Xavier Leroy) ### Compiler distribution build system: - [#2267](https://github.com/ocaml/ocaml/issues/2267): merge generation of header programs, also fixing parallel build on Cygwin. (David Allsopp, review by Sébastien Hinderer) - [#8514](https://github.com/ocaml/ocaml/issues/8514): Use boot/ocamlc.opt for building, if available. (Stephen Dolan, review by Gabriel Scherer) ### Bug fixes: - [#8864](https://github.com/ocaml/ocaml/issues/8864), [#8865](https://github.com/ocaml/ocaml/issues/8865): Fix native compilation of left shift by (word\_size - 1) (Vincent Laviron, report by Murilo Giacometti Rocha, review by Xavier Leroy) - [#2296](https://github.com/ocaml/ocaml/issues/2296): Fix parsing of hexadecimal floats with underscores in the exponent. (Hugo Heuzard and Xavier Leroy, review by Gabriel Scherer) - [#8800](https://github.com/ocaml/ocaml/issues/8800): Fix soundness bug in extension constructor inclusion (Leo White, review by Jacques Garrigue) - [#8848](https://github.com/ocaml/ocaml/issues/8848): Fix x86 stack probe CFI information in caml\_c\_call and caml\_call\_gc (Tom Kelly, review by Xavier Leroy) - [#7156](https://github.com/ocaml/ocaml/issues/7156), [#8594](https://github.com/ocaml/ocaml/issues/8594): make top level use custom printers if they are available (Andrew Litteken, report by Martin Jambon, review by Nicolás Ojeda Bär, Thomas Refis, Armaël Guéneau, Gabriel Scherer, David Allsopp) - [#3249](https://github.com/ocaml/ocaml/issues/3249): ocamlmklib should reject .cmxa files (Xavier Leroy) - [#7937](https://github.com/ocaml/ocaml/issues/7937), [#2287](https://github.com/ocaml/ocaml/issues/2287): fix uncaught Unify exception when looking for type declaration (Florian Angeletti, review by Jacques Garrigue) - [#8610](https://github.com/ocaml/ocaml/issues/8610), [#8613](https://github.com/ocaml/ocaml/issues/8613): toplevel printing, consistent deduplicated name for types (Florian Angeletti, review by Thomas Refis and Gabriel Scherer, reported by Xavier Clerc) - [#8635](https://github.com/ocaml/ocaml/issues/8635), [#8636](https://github.com/ocaml/ocaml/issues/8636): Fix a bad side-effect of the -allow-approx option of ocamldep. It used to turn some errors into successes (Jérémie Dimino) - [#8701](https://github.com/ocaml/ocaml/issues/8701), [#8725](https://github.com/ocaml/ocaml/issues/8725): Variance of constrained parameters causes principality issues (Jacques Garrigue, report by Leo White, review by Gabriel Scherer) - [#8777](https://github.com/ocaml/ocaml/issues/8777)(partial): fix position information in some polymorphic variant error messages about missing tags (Florian Angeletti, review by Thomas Refis) - [#8779](https://github.com/ocaml/ocaml/issues/8779), more cautious variance computation to avoid missing cmis (Florian Angeletti, report by Antonio Nuno Monteiro, review by Leo White) - [#8810](https://github.com/ocaml/ocaml/issues/8810): Env.lookup\_module: don’t allow creating loops (Thomas Refis, report by Leo White, review by Jacques Garrigue) - [#8862](https://github.com/ocaml/ocaml/issues/8862), [#8871](https://github.com/ocaml/ocaml/issues/8871): subst: preserve scopes (Thomas Refis, report by Leo White, review by Jacques Garrigue) - [#8921](https://github.com/ocaml/ocaml/issues/8921), [#8924](https://github.com/ocaml/ocaml/issues/8924): Fix stack overflow with Flambda (Vincent Laviron, review by Pierre Chambart and Leo White, report by Aleksandr Kuzmenko) - [#8944](https://github.com/ocaml/ocaml/issues/8944): Fix “open struct … end” on clambda backend (Thomas Refis, review by Leo White, report by Damon Wang and Mark Shinwell) --- _[View the full topic](https://discuss.ocaml.org/t/ocaml-4-09-0-released/4384)._