Eio
Effects based parallel IO for OCaml.
Eio provides support for concurrency (juggling many tasks) and parallelism (using multiple CPU cores for performance).
It provides facilities for creating and coordinating fibers (light-weight threads) and domains (for parallel processing), as well as interfaces for interacting with resources provided by the operating system.
These features must be used within an event loop, provided by an Eio backend. Applications can use Eio_main.run
to run a suitable loop.
See https://github.com/ocaml-multicore/eio for a tutorial.
module Std : sig ... end
Commonly used standard features. This module is intended to be open
ed.
module Switch : sig ... end
Grouping fibers and other resources so they can be turned off together.
module Fiber : sig ... end
A fiber is a light-weight thread.
module Cancel : sig ... end
Cancelling fibers.
module Promise : sig ... end
A promise is a placeholder for result that will arrive in the future.
module Semaphore : sig ... end
A counting semaphore.
module Mutex : sig ... end
Mutual exclusion.
module Condition : sig ... end
Waiting for a condition to become true.
module Lazy : sig ... end
Delayed evaluation.
module Stream : sig ... end
A stream/queue.
module Pool : sig ... end
A pool of resources.
module Domain_manager : sig ... end
Parallel computation across multiple CPU cores.
module Executor_pool : sig ... end
A pool of domains for executing jobs.
val traceln :
?__POS__:(string * int * int * int) ->
('a, Format.formatter, unit, unit) format4 ->
'a
traceln fmt
outputs a debug message (typically to stderr).
Trace messages are printed by default and do not require logging to be configured first. The message is printed with a newline, and is flushed automatically. traceln
is intended for quick debugging rather than for production code.
Unlike most Eio operations, traceln
will never switch to another fiber; if the OS is not ready to accept the message then the whole domain waits.
It is safe to call traceln
from multiple domains at the same time. Each line will be written atomically.
Examples:
traceln "x = %d" x;
traceln "x = %d" x ~__POS__; (* With location information *)
module Exn : sig ... end
Eio exceptions.
exception Io of Exn.err * Exn.context
module Debug : sig ... end
Control over debugging.
The general pattern here is that each type of resource has a set of functions for using it, plus a provider (Pi
) module to allow defining your own implementations.
The system resources are available from the environment argument provided by your event loop (e.g. Eio_main.run
).
module Resource : sig ... end
Defines the base resource type.
module Flow : sig ... end
A flow can be used to read or write bytes.
module Buf_read : sig ... end
Buffered input and parsing.
module Buf_write : sig ... end
Buffered output and formatting.
module Net : sig ... end
Network sockets and addresses.
module Path : sig ... end
Accessing paths on a file-system.
module File : sig ... end
Operations on open files.
module Fs : sig ... end
File-system types.
module Process : sig ... end
Managing child processes.
module Time : sig ... end
Clocks, time, sleeping and timeouts.
module Stdenv : sig ... end
The standard environment of a process.
module Private : sig ... end
API for use by the scheduler implementation.