2 IPC::MorseSignals - Communicate between processes with Morse signals.
8 use IPC::MorseSignals qw/msend mrecv/;
12 die "fork() failed: $!";
14 local @SIG{qw/USR1 USR2/} = mrecv sub {
15 print STDERR "received $_[0]!\n";
20 msend "hello!\n" => $pid;
24 This module implements a rare form of IPC by sending Morse-like signals
25 through "SIGUSR1" and "SIGUSR2". Both of those signals are used, so you
26 won't be able to keep them for something else when you use this module.
28 But, seriously, use something else for your IPC. :)
32 msend $msg, $pid [, $speed ]
34 Sends the string $msg to the process $pid (or to all the processes @$pid
35 if $pid is an array ref) at $speed bits per second. Default speed is
36 512, don't set it too low or the target will miss bits and the whole
37 message will be crippled.
42 Takes as its sole argument the callback triggered when a complete
43 message is received, and returns two code references that should replace
44 SIGUSR1 and SIGUSR2 signal handlers. Basically, you want to use it like
47 local @SIG{qw/USR1 USR2/} = mrecv sub { ... };
50 This module exports on request its two only functions, "msend" and
54 Each byte of the data string is converted into its bits sequence, with
55 bits of highest weight coming first. All those bits sequences are put
56 into the same order as the characters occur in the stream. The emitter
57 computes then the longuest sequence of successives 0 (say, "m") and 1
58 ("n"). A signature is then chosen :
60 If C(m > n), we take "n+1" times 1 follewed by 1 0 ;
61 Otherwise, we take "m+1" times 0 follewed by 1 1.
63 The signal is then formed by concatenating the signature, the data bits
64 and the reversed signature (i.e. the bits of the signature in the
67 The receiver knows that the signature has been sent when it has catched
68 at least one 0 and one 1. The signal is completely transferred when it
69 has received for the first time the whole reversed signature.
72 This type of IPC is highly unreliable. Send little data at slow speed if
73 you want it to reach its goal.
75 SIGUSR{1,2} seem to interrupt sleep, so it's not a good idea to transfer
76 data to a sleeping process.
79 POSIX (standard since perl 5) and Time::HiRes (standard since perl
83 perlipc for information about signals in perl.
85 For truely useful IPC, search for shared memory, pipes and semaphores.
88 Vincent Pit, "<perl at profvince.com>"
90 You can contact me by mail or on #perl @ FreeNode (Prof_Vince).
93 Please report any bugs or feature requests to "bug-ipc-morsesignals at
94 rt.cpan.org", or through the web interface at
95 <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=IPC-MorseSignals>. I
96 will be notified, and then you'll automatically be notified of progress
97 on your bug as I make changes.
100 You can find documentation for this module with the perldoc command.
102 perldoc IPC::MorseSignals
105 Thanks for the inspiration, mofino ! I hope this module will fill all
109 Copyright 2007 Vincent Pit, all rights reserved.
111 This program is free software; you can redistribute it and/or modify it
112 under the same terms as Perl itself.