The signals are catched each time, not only once.
With exec() this program replaces itself with itself($0) thus starting a fresh copy: 
$sub = sub { exec "perl $0" };
$SIG{INT} = $sub;
$SIG{USR1} = $sub;
$|++;
print (++$counter), sleep 1 while 1

# E:\kod>exec.pl
###>Ctrl+C
# 1234567
# E:\kod>123
###>Ctrl+C
# E:\kod>123
###>Ctrl+C
# E:\kod>123
###>Ctrl+C
# E:\kod>1234567

[download]
 obviously useless code ... my mistake to take ones time ...


In reply to Re: Can't catch signals after an exec? by sh1tn
in thread Can't catch signals after an exec? by mattk

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