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<html><head><title>IO::Seekable (Perl in a Nutshell, 2nd Edition)</title><link rel="stylesheet" type="text/css" href="../style/style1.css" /><meta name="DC.Creator" content="Stephen Spainhour" /><meta name="DC.Format" content="text/xml" scheme="MIME" /><meta name="DC.Language" content="en-US" /><meta name="DC.Publisher" content="O'Reilly & Associates, Inc." /><meta name="DC.Source" scheme="ISBN" content="0596002416L" /><meta name="DC.Subject.Keyword" content="stuff" /><meta name="DC.Title" content="Perl in a Nutshell, 2nd Edition" /><meta name="DC.Type" content="Text.Monograph" /></head><body bgcolor="#ffffff"><img src="gifs/smbanner.gif" usemap="#banner-map" border="0" alt="Book Home" /><map name="banner-map"><area shape="rect" coords="1,-2,616,66" href="index.htm" alt="Java and XSLT" /><area shape="rect" coords="629,-11,726,25" href="jobjects/fsearch.htm" alt="Search this book" /></map><div class="navbar"><table width="684" border="0"><tr><td align="left" valign="top" width="228"><a href="ch08_129.htm"><img src="../gifs/txtpreva.gif" alt="Previous" border="0" /></a></td><td align="center" valign="top" width="228" /><td align="right" valign="top" width="228"><a href="ch08_131.htm"><img src="../gifs/txtnexta.gif" alt="Next" border="0" /></a></td></tr></table></div><h2 class="sect1">8.130. IO::Seekable</h2><p><a name="INDEX-1480" />Intended to be inherited by otherIO::Handle-based objects to provide methods that allow you to seekthe file descriptors. Has no constructor.</p><blockquote><pre class="code">use IO::Seekable;package IO::<em class="replaceable"><tt>XXX</tt></em>;@ISA = qw(IO::Seekable);</pre></blockquote><p>Provides two methods.</p><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>seek</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">fh</em>->seek(<em class="replaceable">offset</em>, <em class="replaceable">whence</em>)</pre><p>Frontend for the corresponding built-in <tt class="literal">seek</tt>function, which sets a filehandle's position in thefile. Takes the following arguments:</p><dl><dt><i><em class="replaceable"><tt>offset</tt></em></i></dt><dd>The offset where you want to set the position.</p></dd><dt><i><em class="replaceable"><tt>whence</tt></em></i></dt><dd>The position in the file that the offset is relative to. Possiblevalues are: <tt class="literal">0</tt> for the beginning of the file,<tt class="literal">1</tt> for the current position, or<tt class="literal">2</tt> for end of file. May also be expressed as thefollowing constants, which are exported:</p><dl><dt><b><tt class="literal">SEEK_SET</tt></b></dt><dd>Beginning of file</p></dd><dt><b><tt class="literal">SEEK_CUR</tt></b></dt><dd>Current position</p></dd><dt><b><tt class="literal">SEEK_END</tt></b></dt><dd>End of file</p></dd></dl></dd></dl></div><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>tell</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$fh->tell( )</pre><p>Frontend for the corresponding built-in <tt class="literal">tell</tt>function, which returns the current file position in bytes (startingfrom 0).</p></div><hr width="684" align="left" /><div class="navbar"><table width="684" border="0"><tr><td align="left" valign="top" width="228"><a href="ch08_129.htm"><img src="../gifs/txtpreva.gif" alt="Previous" border="0" /></a></td><td align="center" valign="top" width="228"><a href="index.htm"><img src="../gifs/txthome.gif" alt="Home" border="0" /></a></td><td align="right" valign="top" width="228"><a href="ch08_131.htm"><img src="../gifs/txtnexta.gif" alt="Next" border="0" /></a></td></tr><tr><td align="left" valign="top" width="228">8.129. IO::Pipe</td><td align="center" valign="top" width="228"><a href="index/index.htm"><img src="../gifs/index.gif" alt="Book Index" border="0" /></a></td><td align="right" valign="top" width="228">8.131. IO::Select</td></tr></table></div><hr width="684" align="left" /><img src="../gifs/navbar.gif" usemap="#library-map" border="0" alt="Library Navigation Links" /><p><p><font size="-1"><a href="copyrght.htm">Copyright © 2002</a> O'Reilly & Associates. All rights reserved.</font></p><map name="library-map"><area shape="rect" coords="1,0,85,94" href="../index.htm"><area shape="rect" coords="86,1,178,103" href="../lwp/index.htm"><area shape="rect" coords="180,0,265,103" href="../lperl/index.htm"><area shape="rect" coords="267,0,353,105" href="../perlnut/index.htm"><area shape="rect" coords="354,1,446,115" href="../prog/index.htm"><area shape="rect" coords="448,0,526,132" href="../tk/index.htm"><area shape="rect" coords="528,1,615,119" href="../cookbook/index.htm"><area shape="rect" coords="617,0,690,135" href="../pxml/index.htm"></map></body></html>⌨️ 快捷键说明
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