NAME

IO::Lambda::Signal - wait for pids and signals

DESCRIPTION

The module provides access to signal-based callbacks, generic signal listener signal, process ID listener pid, and asynchronous version of system call, spawn.

SYNOPSIS

   use strict;
   use IO::Lambda qw(:all);
   use IO::Lambda::Signal qw(pid spawn);

   # pid
   my $pid = fork;
   exec "/bin/ls" unless $pid;
   lambda {
       context $pid, 5;
       pid {
          my $ret = shift;
          print defined($ret) ? ("exitcode(", $ret>>8, ")\n") : "timeout\n";
       }
   }-> wait;

   # spawn
   this lambda {
      context "perl -v";
      spawn {
          my ( $buf, $exitcode, $error) = @_;
          print "buf=[$buf], exitcode=$exitcode, error=$error\n";
      }
   }-> wait;

USAGE

pid ($PID, $TIMEOUT) -> $?|undef

Accepts PID and optional deadline/timeout, returns either process exit status, or undef on timeout. The corresponding lambda is new_pid :

   new_pid ($PID, $TIMEOUT) :: () -> $?|undef

signal ($SIG, $TIMEOUT) -> boolean

Accepts signal name and optional deadline/timeout, returns 1 if signal was caught, or undef on timeout. The corresponding lambda is new_signal :

   new_signal ($SIG, $TIMEOUT) :: () -> boolean

spawn (@LIST) -> ( output, $?, $!)

Calls pipe open on @LIST, read all data printed by the child process, and waits for the process to finish. Returns three scalars - collected output, process exitcode $?, and an error string (usually $!). The corresponding lambda is new_process :

   new_process (@LIST) :: () -> ( output, $?, $!)

Lambda created by new_process has field 'pid' set to the process pid.

LIMITATIONS

spawn doesn't work on Win32, because pipes don't work with win32's select. They do (see the Win32::Process manpage) work with win32-specific WaitforMultipleObjects, which in turn IO::Lambda doesn't work with.

the IPC::Run manpage apparently manages to work on win32 and be compatible with select. I don't think that dragging IPC::Run as a dependency here worth it, but if you need it, send me a working example so I can at least include it here.

SEE ALSO

the IO::Lambda manpage, the perlipc manpage, the IPC::Open2 manpage, the IPC::Run manpage, the Win32::Process manpage.

AUTHOR

Dmitry Karasik, <dmitry@karasik.eu.org>.