Get status of pipe-process

Hi!

I want to use a perl-program to check, whether a program, that feeds a pipe (endless loop) is running or not:
I would use something like:
------------
die "FIFO is no pipe\n" unless (-p "fifo.txt");
$SIG{ALRM} = sub {
  print "Process does NOT feed the pipe!!!\n";
  open(WRITER,">fifo.txt");#make the program end properly -> write to pipe myself <- this does not work?????
  print WRITER "ALARM!\n";
  close(WRITER);
};
alarm(3);
open(READER,"fifo.txt");
while (<READER>){
}
close(READER);
alarm(0);
--------
why does this not work???

another idea:
--------
die "FIFO is no pipe\n" unless (-p "fifo.txt");
if ($pid = fork()) {
  sleep 3;
  kill($pid); #kill child
}else{
  open(FIFO,"fifo.txt");
  while (<FIFO>){
  }
  close FIFO;
  print "PIPE is OK!\n";
  exit;
}
-------
but killing the child would only make the parent exit, but if the pipe is fed afterwards, the child would say "OK"!

any idea how to make this?

thx
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