Your other child processes are keeping the pipe open for the first one. To demonstrate this, just reverse the order in which you close the pipes: 
for (my $i = 3; $i >= 0; $i--) {
  close($handles[$i]);
}

[download]
That is, when the parent forks child #2, it will inherit the parent's pipe to child #1, and that is what is keeping child #1 from seeing EOF.

One solution is to explicit close those handles in the new children: 

if (!open($handles[$i], "|-") {
  ...close $handles[0..$i-1]...
  child(); exit(0);
}

[download]
Update: Corrected index bounds - thanks psini!

In reply to Re: Forked pipe deadlock by pc88mxer
in thread Forked pipe deadlock by Anonymous Monk

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