Getting rid of zombies in perl

Question

I have written a server in perl, waiting for tcp connections. Every time the server receives one, it forks a new child in charge of it and continues listening for another connection.( And so it cannot wait for the SIGCHILD. ) The child does what it is supposed to do and exits, but continues to "live" as a zombie. What is the solution please ?

thanks for your answer el.pescdo the problem is that waitpid blocks the parent. My parent has something else to do. — babak, Jan 03 '14 at 13:12

score 5 · Answer 1 · edited May 23 '17 at 10:29

5

Set $SIG{CHLD} = 'IGNORE'; to have the system handle them for you automatically.

Or set $SIG{CHLD}to a subroutine and waitpid:

use POSIX qw( WNOHANG );

$SIG{CHLD} = sub {
    while( ( my $child = waitpid( -1, WNOHANG ) ) > 0 ) {
        print "SIGNAL CHLD $child\n";
    }
};

If you really want to understand how it works (of course you do! :), you should read perlipc

There is also more info here on Stack Overflow

edited May 23 '17 at 10:29

Community

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answered Jan 03 '14 at 13:10

grebneke

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thank you grebneke. I have been looking for it for a longtime :) – babak Jan 03 '14 at 14:41

Getting rid of zombies in perl

1 Answers1