package eio_linux

v0.9

New features:

• Add eio_posix backend (@talex5 @haesbaert #448 #477, reviewed by @avsm @patricoferris @polytypic). This replaces eio_luv on all platforms except Windows (which will later switch to its own backend). It is a lot faster, provides access to more modern features (such as openat), and can safely share OS resources between domains.
• Add subprocess support (@patricoferris @talex5 #461 #464 #472, reviewed by @haesbaert @avsm). This is the low-level API support for eio_linux and eio_posix. A high-level cross-platform API will be added in the next release.
• Add Fiber.fork_seq (@talex5 #460, reviewed by @avsm). This is a light-weight alternative to using a single-producer, single-consumer, 0-capacity stream, similar to a Python generator function.

Bug fixes:

• eio_linux: make it safe to share FDs across domains (@talex5 #440, reviewed by @haesbaert). It was previously not safe to share file descriptors between domains because if one domain used an FD just as another was closing it, and the FD got reused, then the original operation could act on the wrong file.
• eio_linux: release uring if Linux is too old (@talex5 #476). Avoids a small resource leak.
• eio_linux: improve error handling creating pipes and sockets (@talex5 #474, spotted by @avsm). If we get an error (e.g. too many FDs) then report it to the calling fiber, instead of exiting the event loop.
• eio_linux: wait for uring to finish before exiting (@talex5 #470, reviewed by @avsm). If the main fiber raised an exception then it was possible to exit while a cancellation operation was still in progress.
• eio_main: make EIO_BACKEND handling more uniform (@talex5 #447). Previously this environment variable was only used on Linux. Now all platforms check it.
• Tell dune about EIO_BACKEND (@talex5 #442). If this changes, dune needs to re-run the tests.
• eio_linux: add some missing close-on-execs (@talex5 #441).
• eio_linux: read_exactly fails to update file offset (@talex5 #438).
• Work around dune enabled_if bug on non-Linux systems (@polytypic #475, reviewed by @talex5).
• Use raw system call of getrandom for glibc versions before 2.25 (@zenfey #482).

Documentation:

• Add HACKING.md with hints for working on Eio (@talex5 #443, reviewed by @avsm @polytypic).
• Improve worker pool example (@talex5 #454).
• Add more Conditions documentation (@talex5 #436, reviewed by @haesbaert). This adds a discussion of conditions to the README and provides examples using them to handle signals.
• Condition: fix the example in the docstring (@avsm #468).

Performance:

• Add a network benchmark using an HTTP-like protocol (@talex5 #478, reviewed by @avsm @patricoferris).
• Add a benchmark for reading from /dev/zero (@talex5 #439).

Other changes:

• Add CI for macOS (@talex5 #452).
• Add tests for pread, pwrite and readdir (@talex5 #451).
• eio_linux: split into multiple files (@talex5 #465 #466, reviewed by @avsm).
• Update Dockerfile (@talex5 #471).
• Use dune.3.7.0 (@patricoferris #457).
• Mint exclusive IDs across domains (@TheLortex #480, reported by @haesbaert, reviewed by @talex5). The tracing currently only works with a single domain anyway, but this will change when OCaml 5.1 is released.

v0.8.1

Some build fixes:

• Fix build on various architectures (@talex5 #432).

  • Work around dune %{system} bug.
  • eio_luv: fix max_luv_buffer_size on 32-bit platforms.
• Add missing test-dependency on MDX (@talex5 #430).

v0.8

New features:

• Add Eio.Net.run_server (@bikallem @talex5 #408). Runs an accept loop in one or more domains, with cancellation and graceful shutdown, and an optional maximum number of concurrent connections.
• Add Buf_read.BE and LE parsers (@Cjen1 #399). Parse numbers in various binary formats.
• Add Eio.Buf_read.uint8 (@talex5 #418).

Performance:

• Make Eio.Condition lock-free (@talex5 #397 #381). In addition to being faster, this allows using conditions in signal handlers.
• Make Eio.Semaphore lock-free (@talex5 @polytypic #398).
• Make Eio.Stream lock-free when the capacity is zero (@talex5 #413 #411).
• Make Eio.Promise lock-free (@talex5 #401).

Bug fixes:

• eio_linux: call Uring.submit as needed (@talex5 @bikallem #428). Previously, we could fail to submit a job promptly because the SQE queue was full.
• Fix luv signals (@haesbaert #412). libuv automatically retries polling if it gets EINTR, without giving OCaml signal handlers a chance to run.
• eio_luv: fix some resource leaks (@talex5 @patricoferris #421).
• eio_luv: fix "unavailable signal" error on Windows (@talex5 #420, reported by @nojb).
• Fix Buf_write.BE.uint48 and LE.uint48 (@adatario #418).

Documentation:

• Add example programs (@talex5 #389).
• Update network examples to use run_server (@talex5 #417).
• Add a warning to the tutorial about Fiber.first (@talex5 #394).
• Clarify the epoch used for Eio.Time.now (@bikallem #395).
• Describe secure_random as an infinite source (@patricoferris #426).
• Update README for OCaml 5 release (@talex5 #384 #391 #393).

Other changes:

• Delay setting SIGPIPE handler until the run function is called (@talex5 #420).
• Remove debug-level logging (@talex5 #403).
• eio-luv: improve process.md test (@smondet #414).
• Update to Dune 3 (@talex5 #410).
• Remove test dependency on Astring (@talex5 #402 #404).
• Simplify cancellation logic (@talex5 #396).
• time: Mtime.Spand.to_s has been deprecated in mtime 2.0.0 (@bikallem #385).

v0.7

API changes:

• Unify IO errors as Eio.Io (@talex5 #378). This makes it easy to catch and log all IO errors if desired. The exception payload gives the type and can be used for matching specific errors. It also allows attaching extra information to exceptions, and various functions were updated to do this.
• Add Time.Mono for monotonic clocks (@bikallem @talex5 #338). Using the system clock for timeouts, etc can fail if the system time is changed during the wait.
• Allow datagram sockets to be created without a source address (@bikallem @haesbaert #360). The kernel will allocate an address in this case. You can also now control the reuse_addr and reuse_port options.
• Add File.stat and improve Path.load (@haesbaert @talex5 #339). Path.load now uses the file size as the initial buffer size.
• Add Eio_unix.pipe (@patricoferris #350). This replaces Eio_linux.pipe.
• Avoid short reads from getrandom(2) (@haesbaert #344). Guards against buggy user code that might not handle this correctly.
• Rename Flow.read to Flow.single_read (@talex5 #353). This is a low-level function and it is easy to use it incorrectly by ignoring the possibility of short reads.

Bug fixes:

• Eio_luv: Fix non-tail-recursive continue (@talex5 #378). Affects the Socket_of_fd and Socketpair effects.
• Eio_linux: UDP sockets were not created close-on-exec (@talex5 #360).
• Eio_linux: work around io_uring non-blocking bug (@haesbaert #327 #355). The proper fix should be in Linux 6.1.
• Eio_mock.Backend: preserve backtraces from main (@talex5 #349).
• Don't lose backtrace in Switch.run_internal (@talex5 #369).

Documentation:

• Use a proper HTTP response in the README example (@talex5 #377).
• Document that read_dir excludes "." and ".." (@talex5 #379).
• Warn about both operations succeeding in Fiber.first (@talex5 #358, reported by @iitalics).
• Update README for OCaml 5.0.0~beta2 (@talex5 #375).

Backend-specific changes:

• Eio_luv: add low-level process support (@patricoferris #359). A future release will add Eio_linux support and a cross-platform API for this.
• Expose Eio_luv.Low_level.Stream.write (@patricoferris #359).
• Expose Eio_luv.Low_level.get_loop (@talex5 #371). This is needed if you want to create resources directly and then use them with Eio_luv.
• Eio_linux.Low_level.openfile is gone (@talex5 #378). It was just left-over test code.

v0.6

Changes:

• Update to OCaml 5.0.0~beta1 (@anmonteiro @talex5 #346).
• Add API for seekable read/writes (@nojb #307).
• Add Flow.write (@haesbaert #318). This provides an optimised alternative to copy in the case where you are writing from a buffer.
• Add Net.with_tcp_connect (@bikallem #302). Convenience function for opening a TCP connection.
• Add Eio.Time.Timeout (@talex5 #320). Makes it easier to pass timeouts around.
• Add Eio_mock.Clock (@talex5 #328). Control time in tests.
• Add Buf_read.take_while1 and skip_while1 (@bikallem #309). These fail if no characters match.
• Make the type parameter for Promise.t covariant (@anmonteiro #300).
• Move list functions into a dedicated submodule (@raphael-proust #315).
• Direct implementation of Flow.source_string (@c-cube #317). Slightly faster.

Bug fixes:

• Condition.broadcast must interlock as well (@haesbaert #324).
• Split the reads into no more than 2^32-1 for luv (@haesbaert @talex5 @EduardoRFS #343). Luv uses a 32 bit int for buffer sizes and wraps if the value passed is too big.
• eio_luv: allow Net.connect to be cancelled (@talex5 @nojb #311).
• eio_main: Use dedicated log source (@anmonteiro #326).
• linux_eio: fix kernel version number in log message (@talex5 @nojb #314).
• Account for stack differences in the socketpair test (issue #312) (@haesbaert #313).

Documentation:

• Add Best Practices section to README (@talex5 #299).
• Documentation improvements (@talex5 #295 #337).

v0.5

New features:

• Add Eio.Condition (@TheLortex @talex5 #277). Allows a fiber to wait for some condition to become true.
• Add Eio.Net.getaddrinfo and getnameinfo (@bikallem @talex5 #278 #288 #291). Convert between host names and addresses.
• Add Eio.Debug (@talex5 #276). Currently, this allows overriding the traceln function.
• Buf_write.create: make switch optional (@talex5 #283). This makes things easier for people porting code from Faraday.

Bug fixes:

• Allow sharing of libuv poll handles (@patricoferris @talex5 #279). Luv doesn't allow two callers to watch the same file handle, so we need to handle that in Eio.

Other changes:

• Upgrade to uring 0.4 (@talex5 #290).
• Mention Mutex, Semaphore and Condition in the README (@talex5 #281).

v0.4

Note: Eio 0.4 drops compatibility with OCaml 4.12+domains. Use OCaml 5.0.0~alpha1 instead.

API changes:

• Eio.Dir has gone. Use Eio.Path instead (@talex5 #266 #270).
• Eio_unix.FD.{take,peek} were renamed to take_opt/peek_opt to make way for non-optional versions.

New features:

• Fiber-local storage (@SquidDev #256). Attach key/value bindings to fibers. These are inherited across forks.
• Eio.Path.{unlink,rmdir,rename} (@talex5 #264 #265).
• Eio_main.run can now return a value (@talex5 #263). This is useful for e.g. cmdliner.
• Eio_unix.socketpair (@talex5 #260).
• Fiber.fork_daemon (@talex5 #252). Create a helper fiber that does not prevent the switch from exiting.
• Add Fiber.{iter,map,filter,fiter_map} (@talex5 #248 #250). These are concurrent versions of the corresponding operations in List.

Bug fixes:

• Fix scheduling fairness in luv backend (@talex5 #269).
• Implement remaining shutdown commands for luv (@talex5 #268).
• Fix IPv6 support with uring backend (@haesbaert #261 #262).
• Use Eio.Net.Connection_reset exception in more places (@talex5 #257).
• Report use of closed FDs better (@talex5 #255). Using a closed FD could previously cause the whole event loop to exit.
• Some fixes for cancellation (@talex5 #254).
• Ensure Buf_write still flushes if an exception is raised (@talex5 #246).
• Do not allow close on accept_fork socket (@talex5 #245).

Documentation:

• Document integrations with Unix, Lwt and Async (@talex5 #247).
• Add a Dockerfile for easy testing (@talex5 #224).

v0.3

API changes:

• Net.accept_sub is deprecated in favour of accept_fork (@talex5 #240). Fiber.fork_on_accept, which it used internally, has been removed.
• Allow short writes in Read_source_buffer (@talex5 #239). The reader is no longer required to consume all the data in one go. Also, add Linux_eio.Low_level.writev_single to expose this behaviour directly.
• Eio.Unix_perm is now Eio.Dir.Unix_perm.

New features:

• Add Eio.Mutex (@TheLortex @talex5 #223).
• Add Eio.Buf_write (@talex5 #235). This is a buffered writer for Eio sinks, based on Faraday.
• Add Eio_mock library for testing (@talex5 #228). At the moment it has mock flows and networks.
• Add Eio_mock.Backend (@talex5 #237 #238). Allows running tests without needing a dependency on eio_main. Also, as it is single-threaded, it can detect deadlocks in test code instead of just hanging.
• Add Buf_read.{of_buffer, of_string, parse_string{,_exn}, return} (@talex5 #225).
• Add <*> combinator to Buf_read.Syntax (@talex5 #227).
• Add Eio.Dir.read_dir (@patricoferris @talex5 #207 #218 #219)

Performance:

• Add Buf_read benchmark and optimise it a bit (@talex5 #230).
• Inline Buf_read.consume to improve performance (@talex5 #232).

Bug fixes / minor changes:

• Allow IO to happen even if a fiber keeps yielding (@TheLortex @talex5 #213).
• Fallback for traceln without an effect handler (@talex5 #226). traceln now works outside of an event loop too.
• Check for cancellation when creating a non-protected child context (@talex5 #222).
• eio_linux: handle EINTR when calling getrandom (@bikallem #212).
• Update to cmdliner.1.1.0 (@talex5 #190).

v0.2

• Add support for UDP (@patricoferris #171).
• Rename Fibre to Fiber (@talex5 #195). This is to match the compiler's spelling.
• Switch to luv backend if uring can't be used (@talex5 #203). Useful on Windows with WSL, and also in Docker containers on older systems.

• Eio_linux: cope with lack of fixed chunks (@talex5 #200).

  • If we run out of fixed memory, just use regular memory instead of waiting (which might deadlock).
  • If we try to allocate a fixed buffer and fail, we now just log a warning and continue without one.
• Add support for FD passing with Eio_linux (@talex5 #199).
• Add Eio_unix.FD.as_socket (@talex5 #193). Useful for working with existing libraries that provide a Unix.file_descr, or for receiving FDs from elsewhere (e.g. socket activation). Also, the Luv.{File,Handle}.of_luv functions now allow controlling whether to close the wrapped FD.
• Add Eio_unix.sleep (@talex5 #188). Based on feedback that some people don't want to treat time as a capability. Possibly also useful for debugging race conditions.
• Tidy up forking API (@talex5 #192). Moves some common code out the the individual backends.
• Improve documentation (@talex5 #197 #194 #186 #185). In particular, explain more low-level details about how cancellation works.
• Add an example Eio_null backend (@talex5 #189). This supports creating fibers, promises and cancellation, but provides no IO operations.
• Effect.eff is now Effect.t in OCaml trunk (@talex5 #201).

v0.1

• Initial release.