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<html><head><title>IPC::Open3 (Programming Perl)</title><!-- STYLESHEET --><link rel="stylesheet" type="text/css" href="../style/style1.css"><!-- METADATA --><!--Dublin Core Metadata--><meta name="DC.Creator" content=""><meta name="DC.Date" content=""><meta name="DC.Format" content="text/xml" scheme="MIME"><meta name="DC.Generator" content="XSLT stylesheet, xt by James Clark"><meta name="DC.Identifier" content=""><meta name="DC.Language" content="en-US"><meta name="DC.Publisher" content="O'Reilly & Associates, Inc."><meta name="DC.Source" content="" scheme="ISBN"><meta name="DC.Subject.Keyword" content=""><meta name="DC.Title" content="IPC::Open3"><meta name="DC.Type" content="Text.Monograph"></head><body><!-- START OF BODY --><!-- TOP BANNER --><img src="gifs/smbanner.gif" usemap="#banner-map" border="0" alt="Book Home"><map name="banner-map"><AREA SHAPE="RECT" COORDS="0,0,466,71" HREF="index.htm" ALT="Programming Perl"><AREA SHAPE="RECT" COORDS="467,0,514,18" HREF="jobjects/fsearch.htm" ALT="Search this book"></map><!-- TOP NAV BAR --><div class="navbar"><table width="515" border="0"><tr><td align="left" valign="top" width="172"><a href="ch32_30.htm"><img src="../gifs/txtpreva.gif" alt="Previous" border="0"></a></td><td align="center" valign="top" width="171"><a href="ch32_01.htm">Chapter 32: Standard Modules</a></td><td align="right" valign="top" width="172"><a href="ch32_32.htm"><img src="../gifs/txtnexta.gif" alt="Next" border="0"></a></td></tr></table></div><hr width="515" align="left"><!-- SECTION BODY --><h2 class="sect1">32.31. IPC::Open3</h2><p><blockquote><pre class="programlisting">use IPC::Open3;local(*HIS_IN, *HIS_OUT, *HIS_ERR);$childpid = open3(*HIS_IN, *HIS_OUT, *HIS_ERR, $cmd, @args);print HIS_IN "stuff\n";close(HIS_IN); # Give end of file to kid.@outlines = <HIS_OUT>; # Read till EOF.@errlines = <HIS_ERR>; # XXX: block potential if massiveprint "STDOUT:\n", @outlines, "\n";print "STDERR:\n", @errlines, "\n";close HIS_OUT;close HIS_ERR;waitpid($childpid, 0);if ($?) { print "That child exited with wait status of $?\n";}</pre></blockquote>The <tt class="literal">IPC::Open3</tt> module works like<tt class="literal">IPC::Open2</tt> (the latter is implemented in terms ofthe former), except that <tt class="literal">open3</tt> provides access tothe standard input, the standard output, <em class="emphasis">and</em> thestandard error handles of the program you launch. The same caveatsapply as with <tt class="literal">open2</tt> (see the previous entry), plusa few more. The order of arguments is different in<tt class="literal">open3</tt> than with <tt class="literal">open2</tt>. Insteadof passing the handle to read from first and the handle to write tosecond, this time it's the other way around. Also, with<tt class="literal">open3</tt>, danger of deadlock is even greater thanbefore. If you try to read through end-of-file on one of the child'stwo output handles, but meanwhile there's a great deal of output onthe other handle, the peer process blocks and appears to hang. Useeither the four-argument form of <tt class="literal">select</tt> or thestandard <tt class="literal">IO::Select</tt> module to circumvent this. See<a href="ch16_01.htm">Chapter 16, "Interprocess Communication"</a> for more details.</p><!-- BOTTOM NAV BAR --><hr width="515" align="left"><div class="navbar"><table width="515" border="0"><tr><td align="left" valign="top" width="172"><a href="ch32_30.htm"><img src="../gifs/txtpreva.gif" alt="Previous" border="0"></a></td><td align="center" valign="top" width="171"><a href="index.htm"><img src="../gifs/txthome.gif" alt="Home" border="0"></a></td><td align="right" valign="top" width="172"><a href="ch32_32.htm"><img src="../gifs/txtnexta.gif" alt="Next" border="0"></a></td></tr><tr><td align="left" valign="top" width="172">32.30. IPC::Open2</td><td align="center" valign="top" width="171"><a href="index/index.htm"><img src="../gifs/index.gif" alt="Book Index" border="0"></a></td><td align="right" valign="top" width="172">32.32. Math::BigInt</td></tr></table></div><hr width="515" align="left"><!-- LIBRARY NAV BAR --><img src="../gifs/smnavbar.gif" usemap="#library-map" border="0" alt="Library Navigation Links"><p><font size="-1"><a href="copyrght.htm">Copyright © 2001</a> O'Reilly & Associates. All rights reserved.</font></p><map name="library-map"> <area shape="rect" coords="2,-1,79,99" href="../index.htm"><area shape="rect" coords="84,1,157,108" href="../perlnut/index.htm"><area shape="rect" coords="162,2,248,125" href="../prog/index.htm"><area shape="rect" coords="253,2,326,130" href="../advprog/index.htm"><area shape="rect" coords="332,1,407,112" href="../cookbook/index.htm"><area shape="rect" coords="414,2,523,103" href="../sysadmin/index.htm"></map><!-- END OF BODY --></body></html>⌨️ 快捷键说明
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