witty
asked on
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");
$SIG{ALRM} = sub {
print "Process does NOT feed the pipe!!!\n";
open(WRITER,">fifo.txt");#
print WRITER "ALARM!\n";
close(WRITER);
};
alarm(3);
open(READER,"fifo.txt");
while (<READER>){
}
close(READER);
alarm(0);
--------
why does this not work???
another idea:
--------
die "FIFO is no pipe\n" unless (-p "fifo.txt");
if ($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
michi
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");
$SIG{ALRM} = sub {
print "Process does NOT feed the pipe!!!\n";
open(WRITER,">fifo.txt");#
print WRITER "ALARM!\n";
close(WRITER);
};
alarm(3);
open(READER,"fifo.txt");
while (<READER>){
}
close(READER);
alarm(0);
--------
why does this not work???
another idea:
--------
die "FIFO is no pipe\n" unless (-p "fifo.txt");
if ($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
michi
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jmcg
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