use Carp;
use Symbol qw(gensym qualify);
-$VERSION = 1.0103;
+$VERSION = 1.02;
@ISA = qw(Exporter);
@EXPORT = qw(open3);
=head1 SYNOPSIS
- $pid = open3(\*WTRFH, \*RDRFH, \*ERRFH,
+ $pid = open3(\*CHLD_IN, \*CHLD_OUT, \*CHLD_ERR,
'some cmd and args', 'optarg', ...);
my($wtr, $rdr, $err);
=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.
+connects CHLD_OUT for reading from the child, CHLD_IN for writing to
+the child, and CHLD_ERR for errors. If CHLD_ERR is false, or the
+same file descriptor as CHLD_OUT, then STDOUT and STDERR of the child
+are on the same filehandle. The CHLD_IN will have autoflush turned
+on.
+
+If CHLD_IN begins with C<< <& >>, then CHLD_IN will be closed in the
+parent, and the child will read from it directly. If CHLD_OUT or
+CHLD_ERR 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.
+The filehandles may also be integers, in which case they are understood
+as file descriptors.
+
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.
+C<exec> failures in the child (such as no such file or permission denied),
+are just reported to CHLD_ERR, as it is not possible to trap them.
+
+If the child process dies for any reason, the next write to CHLD_IN is
+likely to generate a SIGPIPE in the parent, which is fatal by default.
+So you may wish to handle this signal.
+
+Note if you specify C<-> as the command, in an analogous fashion to
+C<open(FOO, "-|")> the child process will just be the forked Perl
+process rather than an external command. This feature isn't yet
+supported on Win32 platforms.
open3() does not wait for and reap the child process after it exits.
Except for short programs where it's acceptable to let the operating system
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 See Also
+
+=over 4
+
+=item L<IPC::Open2>
+
+Like Open3 but without STDERR catpure.
+
+=item L<IPC::Run>
+
+This is a CPAN module that has better error handling and more facilities
+than Open3.
+
+=back
+
=head1 WARNING
The order of arguments differs from that of open2().
# ported to Win32 by Ron Schmidt, Merrill Lynch almost ended my career
# fixed for autovivving FHs, tchrist again
# allow fd numbers to be used, by Frank Tobin
+# allow '-' as command (c.f. open "-|"), by Adam Spiers <perl@adamspiers.org>
#
# $Id: open3.pl,v 1.1 1993/11/23 06:26:15 marc Exp $
#
close $_[0] or croak "$Me: close($_[0]) failed: $!";
}
-sub xfileno {
- my ($fh) = @_;
- return $1 if $fh =~ /^=?(\d+)$/; # deal with $fh just being an fd
- return fileno $fh;
+sub fh_is_fd {
+ return $_[0] =~ /\A=?(\d+)\z/;
}
-sub fh_is_fd {
- return $_[0] =~ /^=?\d+$/;
+sub xfileno {
+ return $1 if $_[0] =~ /\A=?(\d+)\z/; # deal with fh just being an fd
+ return fileno $_[0];
}
my $do_spawn = $^O eq 'os2' || $^O eq 'MSWin32';
my($package, $dad_wtr, $dad_rdr, $dad_err, @cmd) = @_;
my($dup_wtr, $dup_rdr, $dup_err, $kidpid);
+ if (@cmd > 1 and $cmd[0] eq '-') {
+ croak "Arguments don't make sense when the command is '-'"
+ }
+
# simulate autovivification of filehandles because
# it's too ugly to use @_ throughout to make perl do it for us
# tchrist 5-Mar-00
$kidpid = $do_spawn ? -1 : xfork;
if ($kidpid == 0) { # Kid
+ # A tie in the parent should not be allowed to cause problems.
+ untie *STDIN;
+ untie *STDOUT;
# 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 && $dup_err
} else {
xopen \*STDERR, ">&STDOUT" if fileno(STDERR) != fileno(STDOUT);
}
+ return 0 if ($cmd[0] eq '-');
local($")=(" ");
- exec @cmd # XXX: wrong process to croak from
- or croak "$Me: exec of @cmd failed";
+ exec @cmd or do {
+ carp "$Me: exec of @cmd failed";
+ eval { require POSIX; POSIX::_exit(255); };
+ exit 255;
+ };
} elsif ($do_spawn) {
# All the bookkeeping of coincidence between handles is
# handled in spawn_with_handles.
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