[p5sagit/p5-mst-13.2.git] / lib / IPC / Open3.pm

package IPC::Open3;

use strict;
no strict 'refs'; # because users pass me bareword filehandles
our ($VERSION, @ISA, @EXPORT);

require Exporter;

use Carp;
use Symbol qw(gensym qualify);

$VERSION	= 1.0103;
@ISA		= qw(Exporter);
@EXPORT		= qw(open3);

=head1 NAME

IPC::Open3, open3 - open a process for reading, writing, and error handling

=head1 SYNOPSIS

    $pid = open3(\*WTRFH, \*RDRFH, \*ERRFH,
		    'some cmd and args', 'optarg', ...);

    my($wtr, $rdr, $err);
    $pid = open3($wtr, $rdr, $err,
		    'some cmd and args', 'optarg', ...);

=head1 DESCRIPTION

Extremely similar to open2(), open3() spawns the given $cmd and
connects RDRFH for reading, WTRFH for writing, and ERRFH for errors.  If
ERRFH is false, or the same file descriptor as RDRFH, then STDOUT and 
STDERR of the child are on the same filehandle.  The WTRFH will have
autoflush turned on.

If WTRFH begins with C<< <& >>, then WTRFH will be closed in the parent, and
the child will read from it directly.  If RDRFH or ERRFH begins with
C<< >& >>, then the child will send output directly to that filehandle.
In both cases, there will be a dup(2) instead of a pipe(2) made.

If either reader or writer is the null string, this will be replaced
by an autogenerated filehandle.  If so, you must pass a valid lvalue
in the parameter slot so it can be overwritten in the caller, or 
an exception will be raised.

open3() returns the process ID of the child process.  It doesn't return on
failure: it just raises an exception matching C</^open3:/>.  However,
C<exec> failures in the child are not detected.  You'll have to 
trap SIGPIPE yourself.

If you try to read from the child's stdout writer and their stderr
writer, you'll have problems with blocking, which means you'll want
to use select() or the IO::Select, which means you'd best use
sysread() instead of readline() for normal stuff.

This is very dangerous, as you may block forever.  It assumes it's
going to talk to something like B<bc>, both writing to it and reading
from it.  This is presumably safe because you "know" that commands
like B<bc> will read a line at a time and output a line at a time.
Programs like B<sort> that read their entire input stream first,
however, are quite apt to cause deadlock.

The big problem with this approach is that if you don't have control
over source code being run in the child process, you can't control
what it does with pipe buffering.  Thus you can't just open a pipe to
C<cat -v> and continually read and write a line from it.

=head1 WARNING

The order of arguments differs from that of open2().

=cut

# &open3: Marc Horowitz <marc@mit.edu>
# derived mostly from &open2 by tom christiansen, <tchrist@convex.com>
# fixed for 5.001 by Ulrich Kunitz <kunitz@mai-koeln.com>
# ported to Win32 by Ron Schmidt, Merrill Lynch almost ended my career
# fixed for autovivving FHs, tchrist again
#
# $Id: open3.pl,v 1.1 1993/11/23 06:26:15 marc Exp $
#
# usage: $pid = open3('wtr', 'rdr', 'err' 'some cmd and args', 'optarg', ...);
#
# spawn the given $cmd and connect rdr for
# reading, wtr for writing, and err for errors.
# if err is '', or the same as rdr, then stdout and
# stderr of the child are on the same fh.  returns pid
# of child (or dies on failure).


# if wtr begins with '<&', then wtr will be closed in the parent, and
# the child will read from it directly.  if rdr or err begins with
# '>&', then the child will send output directly to that fd.  In both
# cases, there will be a dup() instead of a pipe() made.


# WARNING: this is dangerous, as you may block forever
# unless you are very careful.
#
# $wtr is left unbuffered.
#
# abort program if
#   rdr or wtr are null
#   a system call fails

our $Me = 'open3 (bug)';	# you should never see this, it's always localized

# Fatal.pm needs to be fixed WRT prototypes.

sub xfork {
    my $pid = fork;
    defined $pid or croak "$Me: fork failed: $!";
    return $pid;
}

sub xpipe {
    pipe $_[0], $_[1] or croak "$Me: pipe($_[0], $_[1]) failed: $!";
}

# I tried using a * prototype character for the filehandle but it still
# disallows a bearword while compiling under strict subs.

sub xopen {
    open $_[0], $_[1] or croak "$Me: open($_[0], $_[1]) failed: $!";
}

sub xclose {
    close $_[0] or croak "$Me: close($_[0]) failed: $!";
}

my $do_spawn = $^O eq 'os2' || $^O eq 'MSWin32';

sub _open3 {
    local $Me = shift;
    my($package, $dad_wtr, $dad_rdr, $dad_err, @cmd) = @_;
    my($dup_wtr, $dup_rdr, $dup_err, $kidpid);

    # simulate autovivification of filehandles because
    # it's too ugly to use @_ throughout to make perl do it for us
    # tchrist 5-Mar-00

    unless (eval  {
	$dad_wtr = $_[1] = gensym unless defined $dad_wtr && length $dad_wtr;
	$dad_rdr = $_[2] = gensym unless defined $dad_rdr && length $dad_rdr;
	1; }) 
    {
	# must strip crud for croak to add back, or looks ugly
	$@ =~ s/(?<=value attempted) at .*//s;
	croak "$Me: $@";
    } 

    $dad_err ||= $dad_rdr;

    $dup_wtr = ($dad_wtr =~ s/^[<>]&//);
    $dup_rdr = ($dad_rdr =~ s/^[<>]&//);
    $dup_err = ($dad_err =~ s/^[<>]&//);

    # force unqualified filehandles into caller's package
    $dad_wtr = qualify $dad_wtr, $package;
    $dad_rdr = qualify $dad_rdr, $package;
    $dad_err = qualify $dad_err, $package;

    my $kid_rdr = gensym;
    my $kid_wtr = gensym;
    my $kid_err = gensym;

    xpipe $kid_rdr, $dad_wtr if !$dup_wtr;
    xpipe $dad_rdr, $kid_wtr if !$dup_rdr;
    xpipe $dad_err, $kid_err if !$dup_err && $dad_err ne $dad_rdr;

    $kidpid = $do_spawn ? -1 : xfork;
    if ($kidpid == 0) {		# Kid
	# If she wants to dup the kid's stderr onto her stdout I need to
	# save a copy of her stdout before I put something else there.
	if ($dad_rdr ne $dad_err && $dup_err
		&& fileno($dad_err) == fileno(STDOUT)) {
	    my $tmp = gensym;
	    xopen($tmp, ">&$dad_err");
	    $dad_err = $tmp;
	}

	if ($dup_wtr) {
	    xopen \*STDIN,  "<&$dad_wtr" if fileno(STDIN) != fileno($dad_wtr);
	} else {
	    xclose $dad_wtr;
	    xopen \*STDIN,  "<&=" . fileno $kid_rdr;
	}
	if ($dup_rdr) {
	    xopen \*STDOUT, ">&$dad_rdr" if fileno(STDOUT) != fileno($dad_rdr);
	} else {
	    xclose $dad_rdr;
	    xopen \*STDOUT, ">&=" . fileno $kid_wtr;
	}
	if ($dad_rdr ne $dad_err) {
	    if ($dup_err) {
		# I have to use a fileno here because in this one case
		# I'm doing a dup but the filehandle might be a reference
		# (from the special case above).
		xopen \*STDERR, ">&" . fileno $dad_err
		    if fileno(STDERR) != fileno($dad_err);
	    } else {
		xclose $dad_err;
		xopen \*STDERR, ">&=" . fileno $kid_err;
	    }
	} else {
	    xopen \*STDERR, ">&STDOUT" if fileno(STDERR) != fileno(STDOUT);
	}
	local($")=(" ");
	exec @cmd # XXX: wrong process to croak from
	    or croak "$Me: exec of @cmd failed";
    } elsif ($do_spawn) {
	# All the bookkeeping of coincidence between handles is
	# handled in spawn_with_handles.

	my @close;
	if ($dup_wtr) {
	  $kid_rdr = \*{$dad_wtr};
	  push @close, $kid_rdr;
	} else {
	  push @close, \*{$dad_wtr}, $kid_rdr;
	}
	if ($dup_rdr) {
	  $kid_wtr = \*{$dad_rdr};
	  push @close, $kid_wtr;
	} else {
	  push @close, \*{$dad_rdr}, $kid_wtr;
	}
	if ($dad_rdr ne $dad_err) {
	    if ($dup_err) {
	      $kid_err = \*{$dad_err};
	      push @close, $kid_err;
	    } else {
	      push @close, \*{$dad_err}, $kid_err;
	    }
	} else {
	  $kid_err = $kid_wtr;
	}
	require IO::Pipe;
	$kidpid = eval {
	    spawn_with_handles( [ { mode => 'r',
				    open_as => $kid_rdr,
				    handle => \*STDIN },
				  { mode => 'w',
				    open_as => $kid_wtr,
				    handle => \*STDOUT },
				  { mode => 'w',
				    open_as => $kid_err,
				    handle => \*STDERR },
				], \@close, @cmd);
	};
	die "$Me: $@" if $@;
    }

    xclose $kid_rdr if !$dup_wtr;
    xclose $kid_wtr if !$dup_rdr;
    xclose $kid_err if !$dup_err && $dad_rdr ne $dad_err;
    # If the write handle is a dup give it away entirely, close my copy
    # of it.
    xclose $dad_wtr if $dup_wtr;

    select((select($dad_wtr), $| = 1)[0]); # unbuffer pipe
    $kidpid;
}

sub open3 {
    if (@_ < 4) {
	local $" = ', ';
	croak "open3(@_): not enough arguments";
    }
    return _open3 'open3', scalar caller, @_
}

sub spawn_with_handles {
    my $fds = shift;		# Fields: handle, mode, open_as
    my $close_in_child = shift;
    my ($fd, $pid, @saved_fh, $saved, %saved, @errs);
    require Fcntl;

    foreach $fd (@$fds) {
	$fd->{tmp_copy} = IO::Handle->new_from_fd($fd->{handle}, $fd->{mode});
	$saved{fileno $fd->{handle}} = $fd->{tmp_copy};
    }
    foreach $fd (@$fds) {
	bless $fd->{handle}, 'IO::Handle'
	    unless eval { $fd->{handle}->isa('IO::Handle') } ;
	# If some of handles to redirect-to coincide with handles to
	# redirect, we need to use saved variants:
	$fd->{handle}->fdopen($saved{fileno $fd->{open_as}} || $fd->{open_as},
			      $fd->{mode});
    }
    unless ($^O eq 'MSWin32') {
	# Stderr may be redirected below, so we save the err text:
	foreach $fd (@$close_in_child) {
	    fcntl($fd, Fcntl::F_SETFD(), 1) or push @errs, "fcntl $fd: $!"
		unless $saved{fileno $fd}; # Do not close what we redirect!
	}
    }

    unless (@errs) {
	$pid = eval { system 1, @_ }; # 1 == P_NOWAIT
	push @errs, "IO::Pipe: Can't spawn-NOWAIT: $!" if !$pid || $pid < 0;
    }

    foreach $fd (@$fds) {
	$fd->{handle}->fdopen($fd->{tmp_copy}, $fd->{mode});
	$fd->{tmp_copy}->close or croak "Can't close: $!";
    }
    croak join "\n", @errs if @errs;
    return $pid;
}

1; # so require is happy
Commit	Line	Data
a0d0e21e	1	package IPC::Open3;
7e1af8bc	2
	3	use strict;
	4	no strict 'refs'; # because users pass me bareword filehandles
2675ae2b	5	our ($VERSION, @ISA, @EXPORT);
7e1af8bc	6
a0d0e21e	7	require Exporter;
7e1af8bc	8
a0d0e21e	9	use Carp;
8b3e92c6	10	use Symbol qw(gensym qualify);
7e1af8bc	11
8b3e92c6	12	$VERSION = 1.0103;
7e1af8bc	13	@ISA = qw(Exporter);
7e1af8bc	14	@EXPORT = qw(open3);
a0d0e21e	15
f06db76b	16	=head1 NAME
	17
	18	IPC::Open3, open3 - open a process for reading, writing, and error handling
	19
	20	=head1 SYNOPSIS
	21
84902520	22	$pid = open3(\WTRFH, \RDRFH, \*ERRFH,
f06db76b	23	'some cmd and args', 'optarg', ...);
f06db76b	24
2675ae2b	25	my($wtr, $rdr, $err);
	26	$pid = open3($wtr, $rdr, $err,
	27	'some cmd and args', 'optarg', ...);
	28
f06db76b	29	=head1 DESCRIPTION
	30
	31	Extremely similar to open2(), open3() spawns the given $cmd and
	32	connects RDRFH for reading, WTRFH for writing, and ERRFH for errors. If
2675ae2b	33	ERRFH is false, or the same file descriptor as RDRFH, then STDOUT and
	34	STDERR of the child are on the same filehandle. The WTRFH will have
	35	autoflush turned on.
f06db76b	36
2675ae2b	37	If WTRFH begins with C<< <& >>, then WTRFH will be closed in the parent, and
4633a7c4	38	the child will read from it directly. If RDRFH or ERRFH begins with
2675ae2b	39	C<< >& >>, then the child will send output directly to that filehandle.
a24d8dfd	40	In both cases, there will be a dup(2) instead of a pipe(2) made.
f06db76b	41
2675ae2b	42	If either reader or writer is the null string, this will be replaced
	43	by an autogenerated filehandle. If so, you must pass a valid lvalue
	44	in the parameter slot so it can be overwritten in the caller, or
	45	an exception will be raised.
cb1a09d0	46
7e1af8bc	47	open3() returns the process ID of the child process. It doesn't return on
2675ae2b	48	failure: it just raises an exception matching C</^open3:/>. However,
	49	C<exec> failures in the child are not detected. You'll have to
	50	trap SIGPIPE yourself.
f06db76b	51
2675ae2b	52	If you try to read from the child's stdout writer and their stderr
	53	writer, you'll have problems with blocking, which means you'll want
	54	to use select() or the IO::Select, which means you'd best use
	55	sysread() instead of readline() for normal stuff.
	56
	57	This is very dangerous, as you may block forever. It assumes it's
	58	going to talk to something like B<bc>, both writing to it and reading
	59	from it. This is presumably safe because you "know" that commands
	60	like B<bc> will read a line at a time and output a line at a time.
	61	Programs like B<sort> that read their entire input stream first,
7e1af8bc	62	however, are quite apt to cause deadlock.
	63
	64	The big problem with this approach is that if you don't have control
7a2e2cd6	65	over source code being run in the child process, you can't control
7e1af8bc	66	what it does with pipe buffering. Thus you can't just open a pipe to
	67	C<cat -v> and continually read and write a line from it.
	68
2675ae2b	69	=head1 WARNING
	70
	71	The order of arguments differs from that of open2().
	72
7e1af8bc	73	=cut
a0d0e21e	74
	75	# &open3: Marc Horowitz <marc@mit.edu>
	76	# derived mostly from &open2 by tom christiansen, <tchrist@convex.com>
4633a7c4	77	# fixed for 5.001 by Ulrich Kunitz <kunitz@mai-koeln.com>
f55ee38a	78	# ported to Win32 by Ron Schmidt, Merrill Lynch almost ended my career
2675ae2b	79	# fixed for autovivving FHs, tchrist again
a0d0e21e	80	#
	81	# $Id: open3.pl,v 1.1 1993/11/23 06:26:15 marc Exp $
	82	#
	83	# usage: $pid = open3('wtr', 'rdr', 'err' 'some cmd and args', 'optarg', ...);
	84	#
	85	# spawn the given $cmd and connect rdr for
	86	# reading, wtr for writing, and err for errors.
	87	# if err is '', or the same as rdr, then stdout and
	88	# stderr of the child are on the same fh. returns pid
7e1af8bc	89	# of child (or dies on failure).
a0d0e21e	90
a0d0e21e	91
4633a7c4	92	# if wtr begins with '<&', then wtr will be closed in the parent, and
a0d0e21e	93	# the child will read from it directly. if rdr or err begins with
	94	# '>&', then the child will send output directly to that fd. In both
	95	# cases, there will be a dup() instead of a pipe() made.
	96
	97
	98	# WARNING: this is dangerous, as you may block forever
	99	# unless you are very careful.
	100	#
	101	# $wtr is left unbuffered.
	102	#
	103	# abort program if
	104	# rdr or wtr are null
7e1af8bc	105	# a system call fails
a0d0e21e	106
2675ae2b	107	our $Me = 'open3 (bug)'; # you should never see this, it's always localized
a0d0e21e	108
7e1af8bc	109	# Fatal.pm needs to be fixed WRT prototypes.
	110
	111	sub xfork {
	112	my $pid = fork;
	113	defined $pid or croak "$Me: fork failed: $!";
	114	return $pid;
	115	}
	116
	117	sub xpipe {
	118	pipe $_[0], $_[1] or croak "$Me: pipe($_[0], $_[1]) failed: $!";
	119	}
	120
	121	# I tried using a * prototype character for the filehandle but it still
	122	# disallows a bearword while compiling under strict subs.
a0d0e21e	123
7e1af8bc	124	sub xopen {
	125	open $_[0], $_[1] or croak "$Me: open($_[0], $_[1]) failed: $!";
	126	}
	127
	128	sub xclose {
	129	close $_[0] or croak "$Me: close($_[0]) failed: $!";
	130	}
	131
f55ee38a	132	my $do_spawn = $^O eq 'os2' \|\| $^O eq 'MSWin32';
a24d8dfd	133
7e1af8bc	134	sub _open3 {
	135	local $Me = shift;
	136	my($package, $dad_wtr, $dad_rdr, $dad_err, @cmd) = @_;
	137	my($dup_wtr, $dup_rdr, $dup_err, $kidpid);
	138
2675ae2b	139	# simulate autovivification of filehandles because
	140	# it's too ugly to use @_ throughout to make perl do it for us
	141	# tchrist 5-Mar-00
	142
	143	unless (eval {
	144	$dad_wtr = $_[1] = gensym unless defined $dad_wtr && length $dad_wtr;
	145	$dad_rdr = $_[2] = gensym unless defined $dad_rdr && length $dad_rdr;
	146	1; })
	147	{
	148	# must strip crud for croak to add back, or looks ugly
	149	$@ =~ s/(?<=value attempted) at .*//s;
	150	croak "$Me: $@";
	151	}
	152
	153	$dad_err \|\|= $dad_rdr;
a0d0e21e	154
4633a7c4	155	$dup_wtr = ($dad_wtr =~ s/^[<>]&//);
	156	$dup_rdr = ($dad_rdr =~ s/^[<>]&//);
	157	$dup_err = ($dad_err =~ s/^[<>]&//);
a0d0e21e	158
2675ae2b	159	# force unqualified filehandles into caller's package
7e1af8bc	160	$dad_wtr = qualify $dad_wtr, $package;
	161	$dad_rdr = qualify $dad_rdr, $package;
	162	$dad_err = qualify $dad_err, $package;
	163
8b3e92c6	164	my $kid_rdr = gensym;
	165	my $kid_wtr = gensym;
	166	my $kid_err = gensym;
7e1af8bc	167
	168	xpipe $kid_rdr, $dad_wtr if !$dup_wtr;
	169	xpipe $dad_rdr, $kid_wtr if !$dup_rdr;
	170	xpipe $dad_err, $kid_err if !$dup_err && $dad_err ne $dad_rdr;
	171
a24d8dfd	172	$kidpid = $do_spawn ? -1 : xfork;
a24d8dfd	173	if ($kidpid == 0) { # Kid
7e1af8bc	174	# If she wants to dup the kid's stderr onto her stdout I need to
	175	# save a copy of her stdout before I put something else there.
	176	if ($dad_rdr ne $dad_err && $dup_err
	177	&& fileno($dad_err) == fileno(STDOUT)) {
8b3e92c6	178	my $tmp = gensym;
7e1af8bc	179	xopen($tmp, ">&$dad_err");
	180	$dad_err = $tmp;
	181	}
a0d0e21e	182
a0d0e21e	183	if ($dup_wtr) {
8ebc5c01	184	xopen \*STDIN, "<&$dad_wtr" if fileno(STDIN) != fileno($dad_wtr);
a0d0e21e	185	} else {
8ebc5c01	186	xclose $dad_wtr;
8b3e92c6	187	xopen \*STDIN, "<&=" . fileno $kid_rdr;
a0d0e21e	188	}
a0d0e21e	189	if ($dup_rdr) {
8ebc5c01	190	xopen \*STDOUT, ">&$dad_rdr" if fileno(STDOUT) != fileno($dad_rdr);
a0d0e21e	191	} else {
8ebc5c01	192	xclose $dad_rdr;
8b3e92c6	193	xopen \*STDOUT, ">&=" . fileno $kid_wtr;
a0d0e21e	194	}
	195	if ($dad_rdr ne $dad_err) {
	196	if ($dup_err) {
8b3e92c6	197	# I have to use a fileno here because in this one case
	198	# I'm doing a dup but the filehandle might be a reference
	199	# (from the special case above).
	200	xopen \*STDERR, ">&" . fileno $dad_err
8ebc5c01	201	if fileno(STDERR) != fileno($dad_err);
a0d0e21e	202	} else {
8ebc5c01	203	xclose $dad_err;
8b3e92c6	204	xopen \*STDERR, ">&=" . fileno $kid_err;
a0d0e21e	205	}
a0d0e21e	206	} else {
8ebc5c01	207	xopen \*STDERR, ">&STDOUT" if fileno(STDERR) != fileno(STDOUT);
a0d0e21e	208	}
a0d0e21e	209	local($")=(" ");
2675ae2b	210	exec @cmd # XXX: wrong process to croak from
ad973f30	211	or croak "$Me: exec of @cmd failed";
a24d8dfd	212	} elsif ($do_spawn) {
	213	# All the bookkeeping of coincidence between handles is
	214	# handled in spawn_with_handles.
	215
	216	my @close;
	217	if ($dup_wtr) {
8b3e92c6	218	$kid_rdr = \*{$dad_wtr};
8b3e92c6	219	push @close, $kid_rdr;
a24d8dfd	220	} else {
8b3e92c6	221	push @close, \*{$dad_wtr}, $kid_rdr;
a24d8dfd	222	}
a24d8dfd	223	if ($dup_rdr) {
8b3e92c6	224	$kid_wtr = \*{$dad_rdr};
8b3e92c6	225	push @close, $kid_wtr;
a24d8dfd	226	} else {
8b3e92c6	227	push @close, \*{$dad_rdr}, $kid_wtr;
a24d8dfd	228	}
	229	if ($dad_rdr ne $dad_err) {
	230	if ($dup_err) {
8b3e92c6	231	$kid_err = \*{$dad_err};
8b3e92c6	232	push @close, $kid_err;
a24d8dfd	233	} else {
8b3e92c6	234	push @close, \*{$dad_err}, $kid_err;
a24d8dfd	235	}
	236	} else {
	237	$kid_err = $kid_wtr;
	238	}
	239	require IO::Pipe;
	240	$kidpid = eval {
	241	spawn_with_handles( [ { mode => 'r',
8b3e92c6	242	open_as => $kid_rdr,
a24d8dfd	243	handle => \*STDIN },
a24d8dfd	244	{ mode => 'w',
8b3e92c6	245	open_as => $kid_wtr,
a24d8dfd	246	handle => \*STDOUT },
a24d8dfd	247	{ mode => 'w',
8b3e92c6	248	open_as => $kid_err,
a24d8dfd	249	handle => \*STDERR },
	250	], \@close, @cmd);
	251	};
ad973f30	252	die "$Me: $@" if $@;
a0d0e21e	253	}
a0d0e21e	254
7e1af8bc	255	xclose $kid_rdr if !$dup_wtr;
	256	xclose $kid_wtr if !$dup_rdr;
	257	xclose $kid_err if !$dup_err && $dad_rdr ne $dad_err;
	258	# If the write handle is a dup give it away entirely, close my copy
	259	# of it.
	260	xclose $dad_wtr if $dup_wtr;
a0d0e21e	261
	262	select((select($dad_wtr), $\| = 1)[0]); # unbuffer pipe
	263	$kidpid;
	264	}
7e1af8bc	265
7e1af8bc	266	sub open3 {
a24d8dfd	267	if (@_ < 4) {
	268	local $" = ', ';
	269	croak "open3(@_): not enough arguments";
	270	}
7e1af8bc	271	return _open3 'open3', scalar caller, @_
7e1af8bc	272	}
a0d0e21e	273
a24d8dfd	274	sub spawn_with_handles {
	275	my $fds = shift; # Fields: handle, mode, open_as
	276	my $close_in_child = shift;
	277	my ($fd, $pid, @saved_fh, $saved, %saved, @errs);
	278	require Fcntl;
	279
	280	foreach $fd (@$fds) {
	281	$fd->{tmp_copy} = IO::Handle->new_from_fd($fd->{handle}, $fd->{mode});
	282	$saved{fileno $fd->{handle}} = $fd->{tmp_copy};
	283	}
	284	foreach $fd (@$fds) {
	285	bless $fd->{handle}, 'IO::Handle'
	286	unless eval { $fd->{handle}->isa('IO::Handle') } ;
	287	# If some of handles to redirect-to coincide with handles to
	288	# redirect, we need to use saved variants:
	289	$fd->{handle}->fdopen($saved{fileno $fd->{open_as}} \|\| $fd->{open_as},
	290	$fd->{mode});
	291	}
f55ee38a	292	unless ($^O eq 'MSWin32') {
	293	# Stderr may be redirected below, so we save the err text:
	294	foreach $fd (@$close_in_child) {
	295	fcntl($fd, Fcntl::F_SETFD(), 1) or push @errs, "fcntl $fd: $!"
	296	unless $saved{fileno $fd}; # Do not close what we redirect!
	297	}
a24d8dfd	298	}
	299
	300	unless (@errs) {
	301	$pid = eval { system 1, @_ }; # 1 == P_NOWAIT
	302	push @errs, "IO::Pipe: Can't spawn-NOWAIT: $!" if !$pid \|\| $pid < 0;
	303	}
	304
	305	foreach $fd (@$fds) {
	306	$fd->{handle}->fdopen($fd->{tmp_copy}, $fd->{mode});
	307	$fd->{tmp_copy}->close or croak "Can't close: $!";
	308	}
	309	croak join "\n", @errs if @errs;
	310	return $pid;
	311	}
	312
	313	1; # so require is happy