 |  |
use IPC::Open3;
local(*HIS_IN, *HIS_OUT, *HIS_ERR);
$childpid = open3(*HIS_IN, *HIS_OUT, *HIS_ERR, $cmd, @args);
print HIS_IN "stuff\n";
close(HIS_IN); # Give end of file to kid.
@outlines = <HIS_OUT>; # Read till EOF.
@errlines = <HIS_ERR>; # XXX: block potential if massive
print "STDOUT:\n", @outlines, "\n";
print "STDERR:\n", @errlines, "\n";
close HIS_OUT;
close HIS_ERR;
waitpid($childpid, 0);
if ($?) {
print "That child exited with wait status of $?\n";
}
The IPC::Open3 module works like
IPC::Open2 (the latter is implemented in terms of
the former), except that open3 provides access to
the standard input, the standard output, and the
standard error handles of the program you launch. The same caveats
apply as with open2 (see the previous entry), plus
a few more. The order of arguments is different in
open3 than with open2. Instead
of passing the handle to read from first and the handle to write to
second, this time it's the other way around. Also, with
open3, danger of deadlock is even greater than
before. If you try to read through end-of-file on one of the child's
two output handles, but meanwhile there's a great deal of output on
the other handle, the peer process blocks and appears to hang. Use
either the four-argument form of select or the
standard IO::Select module to circumvent this. See
Chapter 16, "Interprocess Communication" for more details.
|  | |
| 32.30. IPC::Open2 |  | 32.32. Math::BigInt |
Copyright © 2002 O'Reilly & Associates. All rights reserved.