1System::Command::ReaperU(s3e)r Contributed Perl DocumentaStyisotnem::Command::Reaper(3)
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NAME

6       System::Command::Reaper - Reap processes started by System::Command
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VERSION

9       version 1.122
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SYNOPSIS

12       This class is used for internal purposes.  Move along, nothing to see
13       here.
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DESCRIPTION

16       The System::Command objects delegate the reaping of child processes to
17       System::Command::Reaper objects. This allows a user to create a
18       System::Command and discard it after having obtained one or more
19       references to its handles connected to the child process.
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21       The typical use case looks like this:
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23           my $fh = System::Command->new( @cmd )->stdout();
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25       The child process is reaped either through a direct call to close() or
26       when the command object and all its handles have been destroyed, thus
27       avoiding zombies (which would be reaped by the system at the end of the
28       main program).
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30       This is possible thanks to the following reference graph:
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32               System::Command
33                |   |   |  ^|
34                v   v   v  !|
35               in out err  !|
36               ^|  ^|  ^|  !|
37               !v  !v  !v  !v
38           System::Command::Reaper
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40       Legend:
41           | normal ref
42           ! weak ref
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44       The System::Command::Reaper object acts as a sentinel, that takes care
45       of reaping the child process when the original System::Command and its
46       filehandles have been destroyed (or when System::Command close() method
47       is being called).
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METHODS

50       System::Command::Reaper supports the following methods:
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52   new
53           my $reaper = System::Command::Reaper->new( $cmd, \%extra );
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55       Create a new System::Command::Reaper object attached to the
56       System::Command object passed as a parameter.
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58       An optional hash reference can be used to pass extra attributes to the
59       object.
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61   close
62           $reaper->close();
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64       Close all the opened filehandles of the main System::Command object,
65       reaps the child process, and updates the main object with the status
66       information of the child process.
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68       "DESTROY" calls close() when the sentinel is being destroyed.
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70   is_terminated
71           if ( $reaper->is_terminated ) {...}
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73       Returns a true value if the underlying process was terminated.
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75       If the process was indeed terminated, collects exit status, etc.
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77   Accessors
78       The attributes of a System::Command::Reaper object are also accessible
79       through a number of accessors.
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81       The object returned by new() will have the following attributes defined
82       (as copied from the System::Command object that created the reaper):
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84       pid The PID of the underlying command.
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86       stdin
87           A filehandle opened in write mode to the child process' standard
88           input.
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90       stdout
91           A filehandle opened in read mode to the child process' standard
92           output.
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94       stderr
95           A filehandle opened in read mode to the child process' standard
96           error output.
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98       After the call to close() or after is_terminated() returns true, the
99       following attributes will be defined:
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101       exit
102           The exit status of the underlying command.
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104       core
105           A boolean value indicating if the command dumped core.
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107       signal
108           The signal, if any, that killed the command.
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AUTHOR

111       Philippe Bruhat (BooK), "<book at cpan.org>"
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ACKNOWLEDGEMENTS

114       This scheme owes a lot to Vincent Pit who on #perlfr provided the
115       general idea (use a proxy to delay object destruction and child process
116       reaping) with code examples, which I then adapted to my needs.
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119       Copyright 2010-2016 Philippe Bruhat (BooK), all rights reserved.
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LICENSE

122       This program is free software; you can redistribute it and/or modify it
123       under the same terms as Perl itself.
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127perl v5.36.0                      2023-02-05        System::Command::Reaper(3)
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