lsh

• Index

Contents

• Functions
• Output
• Children methods

Modules

• lsh
• lsh.cmd
• lsh.cmd.child
• lsh.cmd.status
• lsh.fio
• lsh.fio.fh
• lsh.memfd
• lsh.path
• lsh.pipeline
• lsh.pipeline.children
• lsh.pipeline.pstatus
• lsh.stringx
• lsh.time

Topics

• README

Examples

• cmd_spec.lua
• helper.lua
• libc_spec.lua
• memfd_spec.lua
• nofile_spec.lua
• path_spec.lua
• pipeline_spec.lua
• stringx_spec.lua

Module lsh.pipeline.children

Representation of the running or exited child processes of a pipeline.

Functions

new (pl)

Constructs a new children struct and runs the cmds defined in the pipeline instance.

Output

output

The output of a finished pipeline.

Children methods

type ()	Returns the instance type.
kill (self, signal)	Sends a signal to all child processes.
ids (self)	Returns the array of OS-assigned process identifiers of all child processes.
wait (self)	Waits for all child processes to exit completely, returning their pstatus.
try_wait (self)	Attempts to collect the exit statuses of the child processes if they have already exited.
wait_with_output (self)	Waits for all child processes to exit and returns an output struct with the stdout and stderr handles of the pipeline.

Functions

new (pl)

Constructs a new children struct and runs the cmds defined in the pipeline instance.

Each child instance keeps a clone of its cmd, so you can inspect it.

You do not need to call this function directly. Use lsh.pipeline.run or lsh.pipeline.spawn.

Parameters:

• pl lsh.pipeline

Returns:

lsh.pipeline.children children

Output

output

The output of a finished pipeline.

The pipeline.output method and the wait_with_output method of a children instance return this table.

Fields:

• stdout stdout of pipeline instance (if any)
• stderr stderr of pipeline instance (if any)
• status pstatus struct

Children methods

type ()

Returns the instance type.

Returns:

the string "children"

kill (self, signal)

Sends a signal to all child processes.

For the valid signal names, see lsh.cmd.child.kill.

Parameters:

• self lsh.pipeline.children
• signal string signal name

Returns:

bool true

Or

1. nil
2. string error message

Usage:

local sh = require 'lsh'

local children = sh.pipeline():add(sh.cmd('sleep', 10)):spawn()
children:kill('term')

ids (self)

Returns the array of OS-assigned process identifiers of all child processes.

Not implemented yet.

Parameters:

• self lsh.pipeline.children

Returns:

table array of process identifiers selene: allow(unused_variable)

wait (self)

Waits for all child processes to exit completely, returning their pstatus.

After the first call, this function always returns the same value.

Parameters:

• self lsh.pipeline.children

Returns:

lsh.pipeline.pstatus pstatus struct

try_wait (self)

Attempts to collect the exit statuses of the child processes if they have already exited.

This function does not block the calling thread. It only checks if the child processes exited.

If all child processes exited, it reaps the process IDs and returns pstatus. Later calls return the same pstatus. If the exit statuses are not available yet, it returns false.

Parameters:

• self lsh.pipeline.children

Returns:

lsh.pipeline.pstatus pstatus struct

Or

false

Or

1. nil
2. string error message

wait_with_output (self)

Waits for all child processes to exit and returns an output struct with the stdout and stderr handles of the pipeline.

By default, stdin, stdout and stderr are inherited from the parent. To capture the output in output, set a memfd instance with stdout(sh.memfd()) or stderr(sh.memfd()).

Parameters:

• self lsh.pipeline.children

Returns:

lsh.pipeline.children.output output struct

Or

1. nil
2. string error message