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<html><head><title>Win32::Registry (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="ch22_14.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="ch22_16.htm"><img src="../gifs/txtnexta.gif" alt="Next" border="0" /></a></td></tr></table></div><h2 class="sect1">22.15. Win32::Registry</h2><p><a name="INDEX-3351" /><a name="INDEX-3352" />This module provides access to theWindows Registry, the database that stores information about allparts of your system and software. Many operating-system andapplication behaviors are controlled by Registry data. TheWin32::Registry module gives you a way to access and update registryinformation with Perl.</p><a name="ch22-159-fm2xml" /><blockquote><b>WARNING:</b> Always be careful when making changes to the registry. If vitalsystem information gets changed by mistake, your system could becomeinoperable. Always make certain you have a backup of your registrybefore you start making modifications. </p></blockquote><p>The Registry moduleautomatically creates objects for the top-level registry trees. Theseobjects are created in the <tt class="literal">main:</tt>: namespace, andeach key that you open or create is accessed via one of these rootobjects. The top-level objects are: </p><blockquote><pre class="code">$HKEY_CLASSES_ROOT$HKEY_CURRENT_USER$HKEY_LOCAL_MACHINE$HKEY_USERS$HKEY_PERFORMANCE_DATA$HKEY_CURRENT_CONFIG$HKEY_DYN_DATA</pre></blockquote><p>If you are outside of the main (default) namespace, you shouldpackage declare the keys, e.g., <tt class="literal">$main::HKEY_USERS</tt>.</p><p><a name="INDEX-3353" />The <tt class="literal">Open</tt>method creates new key objects for subtrees or subkeys under anotheropen key object. Initially, a new key is opened from one of the mainkey objects. For example:</p><blockquote><pre class="code">use Win32::Registry;$p = "SOFTWARE\Microsoft\Windows NT\CurrentVersion";$HKEY_LOCAL_MACHINE->Open($p, $CurrVer) || die "Open $!";</pre></blockquote><p>This example creates a key object <tt class="literal">$CurrVer</tt> for the<tt class="literal">CurrentVersion</tt> key for Windows NT. This keycontains several values for the current version of the operatingsystem. With the new key open, you can read or change the values itcontains (every key has at least one unnamed, default value), or openand create subkeys. The <tt class="literal">Open</tt> method can create keyobjects only for existing keys.</p><p>Registry values are represented in Win32::Registry functions by threeelements: the name of the value, the data type of the value, and thevalue itself. There are several different data types for the values.Win32::Registry defines the following constants for these types:</p><dl><dt><b><tt class="literal">REG_SZ</tt></b></dt><dd>String data</p></dd><dt><b><tt class="literal">REG_DWORD</tt></b></dt><dd>Unsigned four-byte integer</p></dd><dt><b><tt class="literal">REG_MULTI_SZ</tt></b></dt><dd>Multiple strings delimited with NULL</p></dd><dt><b><tt class="literal">REG_EXPAND_SZ</tt></b></dt><dd>Strings that expand (e.g., based on environment variables)</p></dd><dt><b><tt class="literal">REG_BINARY</tt></b></dt><dd>Binary data (no particular format is assumed)</p></dd></dl><a name="perlnut2-CHP-22-SECT-15.1" /><div class="sect2"><h3 class="sect2">22.15.1. Win32::Registry Methods</h3><p>The following methods can be used on key objects, either on thepreopened main keys or subkeys that you have already opened.</p><a name="INDEX-3354" /><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>Create</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$key<em class="replaceable">-></em>Create<em class="replaceable">(</em>$<em class="replaceable">newkey</em>, <em class="replaceable">name</em><em class="replaceable">)</em></pre><p><a name="INDEX-3354" />Creates a new key identified by<em class="replaceable">name</em> and saves it as the object referencenamed by <tt class="literal">$</tt><em class="replaceable"><tt>newkey</tt></em>. Ifthe key already exists, this function simply opens the key. New keyscan only be created one level below the key on which<tt class="literal">Create</tt> is used.</p></div><a name="INDEX-3355" /><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>DeleteKey</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">key</em>->DeleteKey(<em class="replaceable">subkey</em>)</pre><p><a name="INDEX-3355" />Deletes a subkey of thecurrent key. This function will delete all values in the subkey andthe subkey itself. A key cannot be deleted if it contains anysubkeys.</p></div><a name="INDEX-3356" /><a name="INDEX-3357" /><a name="INDEX-3358" /><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>DeleteValue</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">key</em>->DeleteValue(<em class="replaceable">name</em>)</pre><p><a name="INDEX-3356" />Deletes a value identifiedby <em class="replaceable"><tt>name</tt></em> from the current key.<a name="INDEX-3357" /><a name="INDEX-3358" /></p></div><a name="INDEX-3359" /><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>GetKeys</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">key</em>->GetKeys($<em class="replaceable">listref</em>)</pre><p><a name="INDEX-3359" />Returns the names of thesubkeys of the current key to the list referenced by<em class="replaceable"><tt>listref</tt></em>.</p></div><a name="INDEX-3360" /><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>GetValues</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">key</em>->GetValues($<em class="replaceable">hashref</em>)</pre><p><a name="INDEX-3360" />Returns the values containedin the current key to the hash referenced by<em class="replaceable"><tt>hashref</tt></em>. Each registry value name is ahash key, while the hash value is a reference to a three-element listcontaining the name of the value, the data type, and the value.</p></div><a name="INDEX-3361" /><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>Load</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">key</em>->Load(<em class="replaceable">subkey</em>, <em class="replaceable">filename</em>)</pre><p><a name="INDEX-3361" />Loads a registry file to the named<em class="replaceable"><tt>subkey</tt></em> from file<em class="replaceable"><tt>filename</tt></em>.</p></div><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>Open</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">parent</em>->Open(<em class="replaceable">keyname</em>, $<em class="replaceable">key</em>)</pre><p>Opens a registry key named in <em class="replaceable">keyname</em> andsaves it as the object reference named by<tt class="literal">$</tt><em class="replaceable"><tt>key</tt></em>.<em class="replaceable"><tt>keyname</tt></em> is the name of a key relative tothe object on which <tt class="literal">Open</tt> is used(<tt class="literal">$</tt><em class="replaceable"><tt>parent</tt></em>).</p></div><a name="INDEX-3362" /><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>QueryKey</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">key</em>->QueryKey($<em class="replaceable">class</em>, $<em class="replaceable">subs</em>, $<em class="replaceable">vals</em>)</pre><p><a name="INDEX-3362" />Retrieves information aboutthe current key and returns it to the named scalar variables. The keyclass is saved in the <em class="replaceable"><tt>class</tt></em> variable (itwill be the null string "" on Win95since it doesn't use key classes). The number ofsubkeys is saved in the<tt class="literal">$</tt><em class="replaceable"><tt>subs</tt></em> variable, and thenumber of values in the current key is saved in<tt class="literal">$</tt><em class="replaceable"><tt>vals</tt></em>.</p></div><a name="INDEX-3363" /><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>QueryValue</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">key</em>->QueryValue(<em class="replaceable">name</em>, $<em class="replaceable">var</em>)</pre><p><a name="INDEX-3363" />Returns the value of theregistry value specified by <em class="replaceable"><tt>name</tt></em> and savesit in the scalar variable<tt class="literal">$</tt><em class="replaceable"><tt>var</tt></em>.</p></div><a name="INDEX-3364" /><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>Save</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">key</em>->Save(<em class="replaceable">filename</em>)</pre><p><a name="INDEX-3364" />Saves the registry tree root and thecurrent key to a file, <em class="replaceable"><tt>filename</tt></em>.</p></div><a name="INDEX-3365" /><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>SetValue</b></font></td><td align="right"><i></i></td></tr></table><hr width="515" size="3" noshade="true" align="left" color="black" /><pre>$<em class="replaceable">key</em><em class="replaceable">-></em>SetValue<em class="replaceable">(</em><em class="replaceable">subkey</em>, <em class="replaceable">type</em>, <em class="replaceable">value</em><em class="replaceable">)</em></pre><p><a name="INDEX-3365" />Sets the default (unnamed)value for the specified subkey of the key object on which<tt class="literal">SetValue</tt> is used. The arguments are:</p><dl><dt><i><em class="replaceable"><tt>subkey</tt></em></i></dt><dd>Name of the subkey</p></dd><dt><i><em class="replaceable"><tt>type</tt></em></i></dt><dd>One of the type constants (listed above) describing the value</p></dd><dt><i><em class="replaceable"><tt>value</tt></em></i></dt><dd>Value of the key</p></dd></dl></div><a name="INDEX-3366" /><div class="refentry"><table width="515" border="0" cellpadding="5"><tr><td align="left"><font size="+1"><b>SetValueEx</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">key</em>->SetValueEx(<em class="replaceable">name</em>, <em class="replaceable">res</em>, <em class="replaceable">type</em>, <em class="replaceable">value</em>)</pre><p><a name="INDEX-3366" />Sets a value specified by<em class="replaceable"><tt>name</tt></em> in the current key (or creates thevalue if it doesn't already exist). The argumentsare:</p><dl><dt><i><em class="replaceable"><tt>res</tt></em></i></dt><dd>A reserved argument for future use (use <tt class="literal">0</tt> as aplaceholder)</p></dd><dt><i><em class="replaceable"><tt>type</tt></em></i></dt><dd>The data type constant (listed above) describing the value</p></dd><dt><i><em class="replaceable"><tt>value</tt></em></i></dt><dd>The value of the key</p></dd></dl></div></div><hr width="684" align="left" /><div class="navbar"><table width="684" border="0"><tr><td align="left" valign="top" width="228"><a href="ch22_14.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="ch22_16.htm"><img src="../gifs/txtnexta.gif" alt="Next" border="0" /></a></td></tr><tr><td align="left" valign="top" width="228">22.14. Win32::Process</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">22.16. Win32::Semaphore</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. 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