On Thu, Jul 27, 2017 at 7:49 PM, Norman Gaywood <ngayw...@gmail.com> wrote:
> my $input = q:to/EOS/; > line of text > another line > EOS > > my $cat = run 'cat', '-n', :in($input.print), :out; > my $output = $cat.out.get; > $cat.in.close; > $cat.out.close; > > say "done"; > say $output; > > But that is not correct. I seem to be missing something. > :in, :out, :err want a filehandle (or will create one if you specify True, which is what pair syntax gives you if you specify one of them without a filehandle). Not a string; and .print applied to a Str does not turn the string into a filehandle, it sends the string to the filehandle in $*OUT. my $cat = run 'cat', '-n', :in, :out; $cat.in.print($input); # this .print, on IO::Handle, prints the string to that handle $cat.in.close; my $output = $cat.out.slurp: :close; Note that you need to be very careful to avoid the "open3" deadlock: pipes have limited buffers, and if you do this all in one thread when the data is large enough to block on write, and the receiving program then blocks on write back to you, you will deadlock. No language can protect you from this. The solution is that either the writer or the reader (or both) needs to be in its own thread so that if one blocks, the other can keep running and eventually clear the block. -- brandon s allbery kf8nh sine nomine associates allber...@gmail.com ballb...@sinenomine.net unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net
