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=head1 NAME |
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|
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Coro::Util - various utility functions. |
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|
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=head1 SYNOPSIS |
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|
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use Coro::Util; |
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|
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=head1 DESCRIPTION |
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|
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This module implements various utility functions, mostly replacing perl |
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functions by non-blocking counterparts. |
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|
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This module is an AnyEvent user. Refer to the L<AnyEvent> |
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documentation to see how to integrate it into your own programs. |
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|
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=over 4 |
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|
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=cut |
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|
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package Coro::Util; |
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|
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no warnings; |
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use strict; |
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|
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use Socket (); |
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|
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use AnyEvent (); |
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use AnyEvent::Socket (); |
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|
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use Coro::State; |
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use Coro::Handle; |
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use Coro::Storable (); |
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use Coro::Semaphore; |
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|
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use base 'Exporter'; |
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|
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our @EXPORT = qw(gethostbyname gethostbyaddr); |
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our @EXPORT_OK = qw(inet_aton fork_eval); |
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|
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our $VERSION = 4.741; |
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|
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our $MAXPARALLEL = 16; # max. number of parallel jobs |
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|
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my $jobs = new Coro::Semaphore $MAXPARALLEL; |
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|
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sub _do_asy(&;@) { |
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my $sub = shift; |
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$jobs->down; |
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my $fh; |
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|
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my $pid = open $fh, "-|"; |
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|
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if (!defined $pid) { |
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die "fork: $!"; |
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} elsif (!$pid) { |
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syswrite STDOUT, join "\0", map { unpack "H*", $_ } &$sub; |
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Coro::State::_exit 0; |
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} |
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|
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my $buf; |
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my $current = $Coro::current; |
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my $w; $w = AnyEvent->io (fh => $fh, poll => 'r', cb => sub { |
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sysread $fh, $buf, 16384, length $buf |
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and return; |
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|
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undef $w; |
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$current->ready; |
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}); |
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|
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&Coro::schedule; |
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&Coro::schedule while $w; |
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|
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$jobs->up; |
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my @r = map { pack "H*", $_ } split /\0/, $buf; |
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wantarray ? @r : $r[0]; |
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} |
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|
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=item $ipn = Coro::Util::inet_aton $hostname || $ip |
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|
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Works almost exactly like its AnyEvent::Socket counterpart, except that it does not |
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block. |
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|
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=cut |
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|
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sub inet_aton { |
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my $current = $Coro::current; |
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my @res; |
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|
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AnyEvent::Socket::inet_aton $_[0], sub { |
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@res = shift; |
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$current->ready; |
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undef $current; |
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}; |
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|
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Coro::schedule while $current; |
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|
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wantarray ? @res : $res[0] |
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} |
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|
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=item gethostbyname, gethostbyaddr |
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|
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Work similarly to their perl counterparts, but do not block. Uses |
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C<Anyevent::Util::inet_aton> internally. |
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|
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=cut |
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|
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sub gethostbyname($) { |
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my $current = $Coro::current; |
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my @res = inet_aton $_[0]; |
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|
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($_[0], $_[0], &Socket::AF_INET, 4, map +(format_ip $_), grep length == 4, @res) |
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} |
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|
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sub gethostbyaddr($$) { |
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_do_asy { gethostbyaddr $_[0], $_[1] } @_ |
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} |
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|
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=item @result = Coro::Util::fork_eval { ... }, @args |
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|
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Executes the given code block or code reference with the given arguments |
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in a separate process, returning the results. The return values must be |
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serialisable with Coro::Storable. It may, of course, block. |
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|
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Note that using event handling in the sub is not usually a good idea as |
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you will inherit a mixed set of watchers from the parent. |
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Exceptions will be correctly forwarded to the caller. |
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|
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This function is useful for pushing cpu-intensive computations into a |
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different process, for example to take advantage of multiple CPU's. Its |
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also useful if you want to simply run some blocking functions (such as |
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C<system()>) and do not care about the overhead enough to code your own |
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pid watcher etc. |
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|
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This function might keep a pool of processes in some future version, as |
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fork can be rather slow in large processes. |
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|
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Example: execute some external program (convert image to rgba raw form) |
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and add a long computation (extract the alpha channel) in a separate |
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process, making sure that never more then $NUMCPUS processes are being |
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run. |
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|
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my $cpulock = new Coro::Semaphore $NUMCPUS; |
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|
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sub do_it { |
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my ($path) = @_; |
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|
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my $guard = $cpulock->guard; |
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|
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Coro::Util::fork_eval { |
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open my $fh, "convert -depth 8 \Q$path\E rgba:" |
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or die "$path: $!"; |
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|
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local $/; |
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# make my eyes hurt |
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pack "C*", unpack "(xxxC)*", <$fh> |
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} |
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} |
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|
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my $alphachannel = do_it "/tmp/img.png"; |
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|
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=cut |
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|
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sub fork_eval(&@) { |
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my ($cb, @args) = @_; |
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|
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pipe my $fh1, my $fh2 |
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or die "pipe: $!"; |
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|
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my $pid = fork; |
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|
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if ($pid) { |
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undef $fh2; |
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|
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my $res = Coro::Storable::thaw +(Coro::Handle::unblock $fh1)->readline (undef); |
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waitpid $pid, 0; # should not block, we expect the child to simply behave |
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die $$res unless "ARRAY" eq ref $res; |
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return wantarray ? @$res : $res->[-1]; |
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|
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} elsif (defined $pid) { |
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delete $SIG{__WARN__}; |
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delete $SIG{__DIE__}; |
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# just in case, this hack effectively disables event processing |
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# in the child. cleaner and slower would be to canceling all |
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# event watchers, but we are event-model agnostic. |
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undef $Coro::idle; |
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$Coro::current->prio (Coro::PRIO_MAX); |
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|
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eval { |
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undef $fh1; |
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|
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my @res = eval { $cb->(@args) }; |
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|
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open my $fh, ">", \my $buf |
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or die "fork_eval: cannot open fh-to-buf in child: $!"; |
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Storable::store_fd $@ ? \"$@" : \@res, $fh; |
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close $fh; |
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|
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syswrite $fh2, $buf; |
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close $fh2; |
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}; |
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warn $@ if $@; |
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Coro::State::_exit 0; |
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|
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} else { |
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die "fork_eval: $!"; |
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} |
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} |
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# make sure store_fd is preloaded |
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eval { Storable::store_fd undef, undef }; |
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|
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1; |
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=back |
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|
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=head1 AUTHOR |
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|
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Marc Lehmann <schmorp@schmorp.de> |
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http://home.schmorp.de/ |
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|
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=cut |
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|
