1Util(3)               User Contributed Perl Documentation              Util(3)
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NAME

6       Coro::Util - various utility functions.
7

SYNOPSIS

9        use Coro::Util;
10

DESCRIPTION

12       This module implements various utility functions, mostly replacing perl
13       functions by non-blocking counterparts.
14
15       Many of these functions exist for the sole purpose of emulating
16       existing interfaces, no matter how bad or limited they are (e.g. no
17       IPv6 support).
18
19       This module is an AnyEvent user. Refer to the AnyEvent documentation to
20       see how to integrate it into your own programs.
21
22       $ipn = Coro::Util::inet_aton $hostname || $ip
23           Works almost exactly like its "Socket::inet_aton" counterpart,
24           except that it does not block other coroutines.
25
26           Does not handle multihomed hosts or IPv6 - consider using
27           "AnyEvent::Socket::resolve_sockaddr" with the Coro rouse functions
28           instead.
29
30       gethostbyname, gethostbyaddr
31           Work similarly to their Perl counterparts, but do not block. Uses
32           "AnyEvent::Util::inet_aton" internally.
33
34           Does not handle multihomed hosts or IPv6 - consider using
35           "AnyEvent::Socket::resolve_sockaddr" or
36           "AnyEvent::DNS::reverse_lookup" with the Coro rouse functions
37           instead.
38
39       @result = Coro::Util::fork_eval { ... }, @args
40           Executes the given code block or code reference with the given
41           arguments in a separate process, returning the results. The return
42           values must be serialisable with Coro::Storable. It may, of course,
43           block.
44
45           Note that using event handling in the sub is not usually a good
46           idea as you will inherit a mixed set of watchers from the parent.
47
48           Exceptions will be correctly forwarded to the caller.
49
50           This function is useful for pushing cpu-intensive computations into
51           a different process, for example to take advantage of multiple
52           CPU's. Its also useful if you want to simply run some blocking
53           functions (such as "system()") and do not care about the overhead
54           enough to code your own pid watcher etc.
55
56           This function might keep a pool of processes in some future
57           version, as fork can be rather slow in large processes.
58
59           You should also look at "AnyEvent::Util::fork_eval", which is newer
60           and more compatible to totally broken Perl implementations such as
61           the one from ActiveState.
62
63           Example: execute some external program (convert image to rgba raw
64           form) and add a long computation (extract the alpha channel) in a
65           separate process, making sure that never more then $NUMCPUS
66           processes are being run.
67
68              my $cpulock = new Coro::Semaphore $NUMCPUS;
69
70              sub do_it {
71                 my ($path) = @_;
72
73                 my $guard = $cpulock->guard;
74
75                 Coro::Util::fork_eval {
76                    open my $fh, "convert -depth 8 \Q$path\E rgba:"
77                       or die "$path: $!";
78
79                    local $/;
80                    # make my eyes hurt
81                    pack "C*", unpack "(xxxC)*", <$fh>
82                 }
83              }
84
85              my $alphachannel = do_it "/tmp/img.png";
86

AUTHOR/SUPPORT/CONTACT

88          Marc A. Lehmann <schmorp@schmorp.de>
89          http://software.schmorp.de/pkg/Coro.html
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93perl v5.32.1                      2021-01-27                           Util(3)
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