1Child(3)              User Contributed Perl Documentation             Child(3)
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3
4

NAME

6       Child - Object oriented simple interface to fork()
7

DESCRIPTION

9       Fork is too low level, and difficult to manage. Often people forget to
10       exit at the end, reap their children, and check exit status. The
11       problem is the low level functions provided to do these things. Throw
12       in pipes for IPC and you just have a pile of things nobody wants to
13       think about.
14
15       Child is an Object Oriented interface to fork. It provides a clean way
16       to start a child process, and manage it afterwords. It provides methods
17       for running, waiting, killing, checking, and even communicating with a
18       child process.
19
20       NOTE: kill() is unpredictable on windows, strawberry perl sends the
21       kill signal to the parent as well as the child.
22

SYNOPSIS

24   BASIC
25           use Child;
26
27           my $child = Child->new(sub {
28               my ( $parent ) = @_;
29               ....
30               # exit() is called for you at the end.
31           });
32           my $proc = $child->start;
33
34           # Kill the child if it is not done
35           $proc->is_complete || $proc->kill(9);
36
37           $proc->wait; #blocking
38
39   IPC
40           # Build with IPC
41           my $child2 = Child->new(sub {
42               my $self = shift;
43               $self->say("message1");
44               $self->say("message2");
45               my $reply = $self->read(1);
46           }, pipe => 1 );
47           my $proc2 = $child2->start;
48
49           # Read (blocking)
50           my $message1 = $proc2->read();
51           my $message2 = $proc2->read();
52
53           $proc2->say("reply");
54
55   SHORTCUT
56       Child can export the child() shortcut function when requested. This
57       function creates and starts the child process in one action.
58
59           use Child qw/child/;
60
61           my $proc = child {
62               my $parent = shift;
63               ...
64           };
65
66       You can also request IPC:
67
68           use Child qw/child/;
69
70           my $child = child {
71               my $parent = shift;
72               ...
73           } pipe => 1;
74

DETAILS

76       First you define a child, you do this by constructing a Child object.
77       Defining a child does not start a new process, it is just the way to
78       define what the new process will look like. Once you have defined the
79       child you can start the process by calling $child->start(). One child
80       object can start as many processes as you like.
81
82       When you start a child an Child::Link::Proc object is returned. This
83       object provides multiple useful methods for interacting with your
84       process. Within the process itself an Child::Link::Parent is created
85       and passed as the only parameter to the function used to define the
86       child. The parent object is how the child interacts with its parent.
87

PROCESS MANAGEMENT METHODS

89       @procs = Child->all_procs()
90           Get a list of all the processes that have been started. This list
91           is cleared in processes when they are started; that is a child will
92           not list its siblings.
93
94       @pids = Child->all_proc_pids()
95           Get a list of all the pids of processes that have been started.
96
97       Child->wait_all()
98           Call wait() on all processes.
99

EXPORTS

101       $proc = child( sub { ... } )
102       $proc = child { ... }
103       $proc = child( sub { ... }, $plugin, @data )
104       $proc = child { ... } $plugin => @data
105           Create and start a process in one action.
106

CONSTRUCTOR

108       $child = Child->new( sub { ... } )
109       $child = Child->new( sub { ... }, $plugin, @plugin_data )
110           Create a new Child object. Does not start the child.
111

OBJECT METHODS

113       $proc = $child->start()
114           Start the child process.
115

SEE ALSO

117       Child::Link::Proc
118           The proc object that is returned by $child->start()
119
120       Child::Link::Parent
121           The parent object that is provided as the argument to the function
122           used to define the child.
123
124       Child::Link::IPC
125           The base class for IPC plugin link objects. This provides the IPC
126           methods.
127

HISTORY

129       Most of this was part of Parallel::Runner intended for use in the
130       Fennec project. Fennec is being broken into multiple parts, this is one
131       such part.
132

FENNEC PROJECT

134       This module is part of the Fennec project. See Fennec for more details.
135       Fennec is a project to develop an extendable and powerful testing
136       framework.  Together the tools that make up the Fennec framework
137       provide a potent testing environment.
138
139       The tools provided by Fennec are also useful on their own. Sometimes a
140       tool created for Fennec is useful outside the greater framework. Such
141       tools are turned into their own projects. This is one such project.
142
143       Fennec - The core framework
144         The primary Fennec project that ties them all together.
145

AUTHORS

147       Chad Granum exodist7@gmail.com
148

COPYRIGHT

150       Copyright (C) 2010 Chad Granum
151
152       Child is free software; Standard perl licence.
153
154       Child is distributed in the hope that it will be useful, but WITHOUT
155       ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
156       FITNESS FOR A PARTICULAR PURPOSE.  See the license for more details.
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160perl v5.30.0                      2019-07-26                          Child(3)