I.e. it appears perl is checking the value of close and putting out the error whether I want it or not. Trying to stop the error with a 'no warnings' just before the final close doesn't silence the message. Only by disabling STDERR and redirecting to to /dev/null (cygwin) then restoring it do I effectively silence the message.

While I don't disagree with the idea of checking 'close' for errors (and usually do so). It would be nice to be able to tell perl not to warn me about problems there.

Does {local $SIG{PIPE} = sub {}; close($pipe)} work? My guess is that perl is checking the status of the pipe and emulating SIGPIPE when you close it.

Does it work 'where'? I had it bracketing the write call and added bracketing for the close statement:

    sub close_child_io () {
      Debug "SigCHLD: close iopair[1]";
      local * pipe_catch = sub ($) { Debug "Child already closed";
        $iopair[1] = $iopair[0] = undef; };
      my $tmp = $PathTree::iopair[1];
      $PathTree::iopair[1] = undef;
      $SIG{PIPE}=\&pipe_catch;
      close($tmp);
      $SIG{PIPE}='DEFAULT';
    };
[download]

Only the "using-TNT-to-kill-a-fly" idea of redirecting STDERR to /dev/null before every write through perl seems to shut it up:

|2588     local * write_child = sub ($) {
|2589       my $out=$_[0];
|2590       return unless $iopair[1] and ref $iopair[1] and -w $iopair
+[1];
|2591
|2592       local * pipe_catch = sub ($) { Debug "Child closed";
|2593         $iopair[1] = $iopair[0] = undef; };
|2594
|2595       $SIG{PIPE}=\&pipe_catch;
|2596       no warnings;
|2597       open (OLDERR, ">&", \*STDERR) or die "Can't dup STDERR: $!
+";
|2598       open (STDERR, ">", "/dev/null") or die "Can't redirect STD
+ERR to /dev/null: $!";
|2599       select STDERR; $|=1;
|2600       P $iopair[1], $out."\n" ;
|2601       open(STDERR, ">&OLDERR") or die "Can't restore stderr: $!"
+;
|2602       $SIG{PIPE}='DEFAULT';
|2603     };
[download]