NAME
    IPC::Open3::Callback - An extension to IPC::Open3 that will feed out and
    err to callbacks instead of requiring the caller to handle them.

VERSION
    version 1.07

SYNOPSIS
      use IPC::Open3::Callback;
      my $runner = IPC::Open3::Callback->new( {
          out_callback => sub {
              my $data = shift;
              my $pid = shift;

              print( "$pid STDOUT: $data\n" );
          },
          err_callback => sub {
              my $data = shift;
              my $pid = shift;

              print( "$pid STDERR: $data\n" );
          } } );
      my $exit_code = $runner->run_command( 'echo Hello World' );

      use IPC::Open3::Callback qw(safe_open3);
      my ($pid, $in, $out, $err) = safe_open3( "echo", "Hello", "world" ); 
      $buffer = '';
      my $select = IO::Select->new();
      $select->add( $out );
      while ( my @ready = $select->can_read( 5 ) ) {
          foreach my $fh ( @ready ) {
              my $line;
              my $bytes_read = sysread( $fh, $line, 1024 );
              if ( ! defined( $bytes_read ) && !$!{ECONNRESET} ) {
                  die( "error in running ('echo $echo'): $!" );
              }
              elsif ( ! defined( $bytes_read) || $bytes_read == 0 ) {
                  $select->remove( $fh );
                  next;
              }
              else {
                  if ( $fh == $out ) {
                      $buffer .= $line;
                  }
                  else {
                      die( "impossible... somehow got a filehandle i dont know about!" );
                  }
              }
          }
      } 
      waitpid( $pid, 0 );
      my $exit_code = $? >> 8;
      print( "$pid exited with $exit_code: $buffer\n" ); # 123 exited with 0: Hello World

DESCRIPTION
    This module feeds output and error stream from a command to supplied
    callbacks. Thus, this class removes the necessity of dealing with
    IO::Select by hand and also provides a workaround for the bad reputation
    associated with Microsoft Windows' IPC.

EXPORT_OK
  safe_open3( $command, $arg1, ..., $argN )
    Passes the command and arguments on to "open3" and returns a list
    containing:

    pid The process id of the forked process.

    stdin
        An IO::Handle to STDIN for the process.

    stdout
        An IO::Handle to STDOUT for the process.

    stderr
        An IO::Handle to STDERR for the process.

    As with "open3", it is the callers responsibility to "waitpid" to ensure
    forked processes do not become zombies.

    This method works for both *nix and Microsoft Windows OS's. On a Windows
    system, it will use sockets per
    <http://www.perlmonks.org/index.pl?node_id=811150>.

CONSTRUCTORS
  new( \%options )
    The constructor creates a new Callback object and optionally sets global
    callbacks for "STDOUT" and "STDERR" streams from commands that will get
    run by this object (can be overridden per call to run_command). The
    currently available options are:

    out_callback
        out_callback

    err_callback
        err_callback

    buffer_output
        buffer_output

    buffer_size
        buffer_size

    select_timeout
        select_timeout

ATTRIBUTES
  get_buffer_output()
  set_buffer_output( $boolean )
    A boolean value, if true, will buffer output and send to callback one
    line at a time (waits for '\n'). Otherwise, sends text in the same
    chunks returned by sysread.

  get_buffer_size()
  set_buffer_size( $bytes )
    The size of the read buffer (in bytes) supplied to "sysread".

  get_err_callback()
  set_err_callback( &subroutine )
    A subroutine that will be called for each chunk of text written to
    "STDERR". The subroutine will be called with the same 2 arguments as
    out_callback.

  get_last_command()
    The last command run by the run_command method.

  get_out_callback()
  set_out_callback( &subroutine )
    A subroutine that will be called whenever a chunk of output is sent to
    STDOUT by the opened process. The subroutine will be called with 2
    arguments:

    data
        A chunk of text written to the stream

    pid The pid of the forked process

  get_pid()
    Will return the pid of the currently running process. This pid is set by
    "run_command" and will be cleared out when the "run_command" completes.

  get_select_timeout()
  set_select_timeout( $seconds )
    The timeout, in seconds, provided to "IO::Select", by default 0 meaning
    no timeout which will cause the loop to block until output is ready on
    either "STDOUT" or "STDERR".

METHODS
  run_command( $command, $arg1, ..., $argN, \%options )
    Will run the specified command with the supplied arguments by passing
    them on to safe_open3. Arguments can be embedded in the command string
    and are thus optional.

    If the last argument to this method is a hashref ("ref(@_[-1]) eq
    'HASH'"), then it is treated as an options hash. The supported allowed
    options are the same as the constructor and will be used in preference
    to the values set by the constructor or any of the setters. These
    options will be used for this single call, and will not modify the
    "Callback" object itself.

    Returns the exit code from the command.

AUTHORS
    *   Lucas Theisen <lucastheisen@pastdev.com>

    *   Alceu Rodrigues de Freitas Junior <arfreitas@cpan.org>

COPYRIGHT AND LICENSE
    This software is copyright (c) 2013 by Lucas Theisen.

    This is free software; you can redistribute it and/or modify it under
    the same terms as the Perl 5 programming language system itself.

SEE ALSO
    Please see those modules/websites for more information related to this
    module.

    *   IPC::Open3

    *   IPC::Open3::Callback::Command

    *   IPC::Open3::Callback::CommandRunner

    *   <https://github.com/lucastheisen/ipc-open3-callback>

    *   <http://stackoverflow.com/q/16675950/516433>