I'm having some trouble with IPC::Open3. Here is a test script that demonstrates the problem: 
#!/usr/bin/perl

use warnings;
use strict;

use IPC::Open3;

# Basic setup stuff
open(SAVE_STDOUT,">&",STDOUT) or die "save stdout failed";
open(DEVNULL,"< /dev/null") or die "open /dev/null failed";

# Now set STDOUT to a filehandle on a new descriptor
open(FH1,"> /dev/null") or die "open /dev/null failed";
*STDOUT = *FH1;

# Run the command
open3(*DEVNULL, *PIPE, undef, "/bin/sh","-c",<<EOF) or die "open3 fail
+ed";
printf "out 1\\nout 2\\nout 3\\n"
printf "err 1\\nerr 2\\nerr 3\\n" >&2
EOF
;

# And copy the output
open(STDOUT,">&",*SAVE_STDOUT) or die "restore stout failed";
while (<PIPE>) {
  print "PIPE: ",$_;
}
close(PIPE) or die "close pipe failed";

exit(0);

[download]
The expected output from this is: 
PIPE: out 1
PIPE: out 2
PIPE: out 3
PIPE: err 1
PIPE: err 2
PIPE: err 3

[download]
which indicates that the child process had both standard output and standard error sent to the pipe created by open3. Instead, with both IPC::Open3 1.02 and 1.03, I get this output: 
out 1
out 2
out 3
PIPE: err 1
PIPE: err 2
PIPE: err 3

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This indicates that the standard output from the script didn't go through the pipe. Instead it went directly to my terminal, where file descriptor #1 is connected to in the parent process.

This appears to be the result of a bug in IPC::Open3, which I reported in Perl bug #66224, including a patch. I wanted to see if my fellow Monks had any insight or ideas for a better fix/workaround.

Thanks!


--
sgifford's Web page

In reply to IPC::Open3 misbehaving when STDOUT is not FD #1 by sgifford

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