containers

A modular, clean and powerful extension of the OCaml standard library
Library containers.unix
Module CCUnix

High-level Functions on top of Unix

Some useful functions built on top of Unix.

status: unstable

  • since 0.10
type 'a or_error = ( 'a, string ) result
type 'a gen = unit -> 'a option

Calling Commands

val escape_str : string -> string

Escape a string so it can be a shell argument.

type call_result = < stdout : string ; stderr : string ; status : Unix.process_status ; errcode : int >
val call_full : ?bufsize:int -> ?stdin:[ `Gen of string gen | `Str of string ] -> ?env:string array -> ( 'a, Buffer.t, unit, call_result ) format4 -> 'a

call_full cmd wraps the result of Unix.open_process_full cmd into an object. It reads the full stdout and stderr of the subprocess before returning.

  • parameter stdin

    if provided, the generator or string is consumed and fed to the subprocess input channel, which is then closed.

  • parameter bufsize

    buffer size used to read stdout and stderr.

  • parameter env

    environment to run the command in.

val call : ?bufsize:int -> ?stdin:[ `Gen of string gen | `Str of string ] -> ?env:string array -> ( 'a, Buffer.t, unit, string * string * int ) format4 -> 'a

call cmd is similar to call_full cmd but returns a tuple stdout, stderr, errcode instead of an object.

val call_stdout : ?bufsize:int -> ?stdin:[ `Gen of string gen | `Str of string ] -> ?env:string array -> ( 'a, Buffer.t, unit, string ) format4 -> 'a
type line = string
type async_call_result = < stdout : line gen ; stderr : line gen ; stdin : line -> unit ; close_in : unit ; close_err : unit ; close_out : unit ; close_all : unit ; wait : Unix.process_status ; wait_errcode : int >

A subprocess for interactive usage (read/write channels line by line)

  • since 0.11
val async_call : ?env:string array -> ( 'a, Buffer.t, unit, async_call_result ) format4 -> 'a

Spawns a subprocess, like call, but the subprocess's channels are line generators and line sinks (for stdin). If p is async_call "cmd", then p#wait waits for the subprocess to die. Channels can be closed independently.

  • since 0.11

Accessors

  • since 0.11
val stdout : < stdout : 'a.. > -> 'a
val stderr : < stderr : 'a.. > -> 'a
val status : < status : 'a.. > -> 'a
val errcode : < errcode : 'a.. > -> 'a

Simple IO

val with_in : ?mode:int -> ?flags:Unix.open_flag list -> string -> f:( in_channel -> 'a ) -> 'a

Open an input file with the given optional flag list, calls the function on the input channel. When the function raises or returns, the channel is closed.

  • parameter flags

    opening flags. Unix.O_RDONLY is used in any cases.

  • since 0.16
val with_out : ?mode:int -> ?flags:Unix.open_flag list -> string -> f:( out_channel -> 'a ) -> 'a

Same as with_in but for an output channel.

  • parameter flags

    opening flags (default [Unix.O_CREAT; Unix.O_TRUNC]) Unix.O_WRONLY is used in any cases.

  • since 0.16

Subprocesses

val with_process_in : string -> f:( in_channel -> 'a ) -> 'a

Open a shell command in a subprocess and obtain a handle to its stdout.

CCUnix.with_process_in "ls /tmp" ~f:CCIO.read_lines_l;;
  • since 0.16
val with_process_out : string -> f:( out_channel -> 'a ) -> 'a

Open a shell command in a subprocess and obtain a handle to its stdin.

  • since 0.16
type process_full = < stdin : out_channel ; stdout : in_channel ; stderr : in_channel ; close : Unix.process_status >

Handle to a subprocess.

  • since 0.16
val with_process_full : ?env:string array -> string -> f:( process_full -> 'a ) -> 'a

Open a subprocess and obtain a handle to its channels.

  • parameter env

    environment to pass to the subprocess.

  • since 0.16
val ensure_session_leader : unit -> unit

On unix, call Unix.setsid() to make sure subprocesses die at the same time as the current process. Does nothing on windows. Idempotent: it can be called several times but will only have effects, if any, the first time.

  • since 2.8

Networking

val with_connection : Unix.sockaddr -> f:( in_channel -> out_channel -> 'a ) -> 'a

Wrap Unix.open_connection with a handler.

  • since 0.16
exception ExitServer
val establish_server : Unix.sockaddr -> f:( in_channel -> out_channel -> _ ) -> unit

Listen on the address and calls the handler in a blocking fashion. Using Thread is recommended if handlers might take time. The callback should raise ExitServer to stop the loop.

  • since 0.16

File lock

val with_file_lock : kind:[ `Read | `Write ] -> string -> ( unit -> 'a ) -> 'a

with_file_lock ~kind filename f puts a lock on the offset 0 of the file named filename, calls f and returns its result after the file is unlocked. If f () raises an exception the exception is re-raised after the file is unlocked.

  • parameter kind

    specifies whether the lock is read-only or read-write.

  • since 1.2

Infix Functions

module Infix : sig ... end
include module type of Infix
val (?|) : ( 'a, Buffer.t, unit, call_result ) format4 -> 'a

Infix version of call.

  • since 0.11
val (?|&) : ( 'a, Buffer.t, unit, async_call_result ) format4 -> 'a

Infix version of async_call.

  • since 0.11

Temporary directory

val with_temp_dir : ?mode:int -> ?dir:string -> string -> ( string -> 'a ) -> 'a

Create a temporary directory, call the function, and then destroy the directory afterwards. Usage with_temp_dir pattern f.

  • parameter pattern

    the naming pattern for the temporary directory. Helps avoiding collisions.

  • parameter mode

    mode for the directory

  • parameter dir

    the directory under which to make a temporary directory (default /tmp)

    Note that this is implemented following the discussion at: https://discuss.ocaml.org/t/how-to-create-a-temporary-directory-in-ocaml/1815/

  • since 2.8