| Subject: | start \@cat, '<pipe', \*IN; doesn't work as advertised (doesn't work at all?) |
| Date: | Wed, 26 Apr 2017 07:11:19 +0200 |
| To: | bug-IPC-Run [...] rt.cpan.org |
| From: | Peter Valdemar Mørch <peter [...] morch.com> |
Hi,
The perldoc has this example :
@cat = ( 'cat' );
....
$h = start \@cat, '<pipe', \*IN;
print IN "hello world\n";
pump $h;
close IN;
finish $h;
But it doesn't work... It hangs and never finishes. Swapping the pump and
close lines, works, though. Like this:
$h = start \@cat, '<pipe', \*IN;
print IN "hello world\n";
close IN;
pump $h;
finish $h;
I think I understand that - cat doesn't print until STDIN has been closed
(although that doesn't jive with experiments in a normal terminal)
So then I tried this: Here I just need a single line of input. It also
doesn't work:
my $bashScript = <<'END';
echo starting - Enter a line and press enter:
read LINE
echo Got line: $LINE
echo ending
END
my $h = start ['bash', '-c', $bashScript], '<pipe', \*IN;
print IN "hello world\n";
pump $h;
close IN;
finish $h;
I don't actually understand why that doesn't work, when this does (using a
scalar and '<' instead of a glob and '<pipe'):
my $bashScript = <<'END';
echo starting - Enter a line and press enter:
read LINE
echo Got line: $LINE
echo ending
END
my $in = '';
my $h = start ['bash', '-c', $bashScript], '<', \$in;
$in .= "hello world\n";
pump $h;
finish $h;
However this does work. I can't explain that from reading the perldoc...
my $bashScript = <<'END';
echo starting - Enter a line and press enter:
read LINE
echo Got line: $LINE
echo ending
END
my $h = start ['bash', '-c', $bashScript], '<pipe', \*IN, '>', sub {
print @_ };
print IN "hello world\n";
pump $h;
close IN;
finish $h;
Using IPC::Run version: 0.95, perl v5.20.2, debian jessie (stable).
--
Peter Valdemar Mørch
http://www.morch.com