I don't care much about what ikagami said exactly, but you did kill the program is what he noticed, and that is what I focus on. As far as I'm concerned that is the reason why your example does not print anything. Maybe a piece of code will help:

use strict ;
use warnings ;
alarm 2 ;
$SIG{'ALRM'} = sub{ print "Timeout reached" } ;
$SIG{'INT'} = sub { exit(0) } ;
<> ;
__END__
[/tmp] # perl pltst1.pl
^C[/tmp] # perl pltst1.pl
^CTimeout reached[/tmp] #

(1. ctrl-c pressed < 2 seconds
 2. ctrl-c pressed > 2 seconds)

[download]

1. So you see, it does matter if you kill the program. 2. Whether something is being outputted to STDOUT is not a secondary issue. It matters everything. STDERR and STDOUT buffer mechanisms are fundamentaly different.

edit: So if people are down-voting this that is fine, but then at least show me where I am wrong please.

edit 2: Examples added regards the difference between STDOUT and STDERR below (Pevious example was Linux, this was on Windows):

WITH syswrite STDERR and print STDERR:

use strict ;
use warnings ;

alarm 2 ;
$SIG{ALRM} = sub{
    syswrite STDERR, "s Timeout reached " ;
    print STDERR "p Timeout reached " ;
} ; 
sleep(4) ;
syswrite STDERR, "s Program end " ;
print STDERR "p Program end " ;
sleep(2) ;
__END__
C:\perlproject>perl sigtst.pl
s Timeout reached p Timeout reached s Program end p Program end

s Timeout reached - Printed after 2 seconds
p Timeout reached - Printed after 2 seconds
s Program end     - Printed after 4 seconds
p Program end     - Printed after 4 seconds

[download]

WITH syswrite STDOUT and print STDOUT:

use strict ;
use warnings ;

alarm 2 ;
$SIG{ALRM} = sub{
    syswrite STDOUT, "s Timeout reached " ;
    print STDOUT "p Timeout reached " ;
} ; 
sleep(4) ;
syswrite STDOUT, "s Program end " ;
print STDOUT "p Program end " ;
sleep(2) ;
__END__
C:\perlproject>perl sigtst.pl
s Timeout reached s Program end p Timeout reached p Program end

s Timeout reached - Printed after 2 seconds
s Program end     - Printed after 4 seconds
p Timeout reached - Printed after 6 seconds
p Program end     - Printed after 6 seconds

[download]

In reply to Re^13: Print inside SIGNALS by Veltro
in thread Print inside SIGNALS by pedrete

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