mingw/html/lib/Cwd.html

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  13 <big><strong><span class="block">&nbsp;Cwd - get pathname of current working directory</span></strong></big>
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  16
  17 <p><a name="__index__"></a></p>
  18 <!-- INDEX BEGIN -->
  19
  20 <ul>
  21
  22         <li><a href="#name">NAME</a></li>
  23         <li><a href="#synopsis">SYNOPSIS</a></li>
  24         <li><a href="#description">DESCRIPTION</a></li>
  25         <ul>
  26
  27                 <li><a href="#getcwd_and_friends">getcwd and friends</a></li>
  28                 <li><a href="#abs_path_and_friends">abs_path and friends</a></li>
  29                 <li><a href="#_env_pwd_">$ENV{PWD}</a></li>
  30         </ul>
  31
  32         <li><a href="#notes">NOTES</a></li>
  33         <li><a href="#author">AUTHOR</a></li>
  34         <li><a href="#copyright">COPYRIGHT</a></li>
  35         <li><a href="#see_also">SEE ALSO</a></li>
  36 </ul>
  37 <!-- INDEX END -->
  38
  39 <hr />
  40 <p>
  41 </p>
  42 <h1><a name="name">NAME</a></h1>
  43 <p>Cwd - get pathname of current working directory</p>
  44 <p>
  45 </p>
  46 <hr />
  47 <h1><a name="synopsis">SYNOPSIS</a></h1>
  48 <pre>
  49     use Cwd;
  50     my $dir = getcwd;</pre>
  51 <pre>
  52     use Cwd 'abs_path';
  53     my $abs_path = abs_path($file);</pre>
  54 <p>
  55 </p>
  56 <hr />
  57 <h1><a name="description">DESCRIPTION</a></h1>
  58 <p>This module provides functions for determining the pathname of the
  59 current working directory.  It is recommended that getcwd (or another
  60 *cwd() function) be used in <em>all</em> code to ensure portability.</p>
  61 <p>By default, it exports the functions cwd(), getcwd(), fastcwd(), and
  62 <a href="#item_fastgetcwd"><code>fastgetcwd()</code></a> (and, on Win32, <a href="#item_getdcwd"><code>getdcwd())</code></a> into the caller's namespace.</p>
  63 <p>
  64 </p>
  65 <h2><a name="getcwd_and_friends">getcwd and friends</a></h2>
  66 <p>Each of these functions are called without arguments and return the
  67 absolute path of the current working directory.</p>
  68 <dl>
  69 <dt><strong><a name="item_getcwd">getcwd</a></strong>
  70
  71 <dd>
  72 <pre>
  73     my $cwd = getcwd();</pre>
  74 </dd>
  75 <dd>
  76 <p>Returns the current working directory.</p>
  77 </dd>
  78 <dd>
  79 <p>Re-implements the <a href="#item_getcwd"><code>getcwd(3)</code></a> (or <code>getwd(3))</code> functions in Perl.</p>
  80 </dd>
  81 <dt><strong><a name="item_cwd">cwd</a></strong>
  82
  83 <dd>
  84 <pre>
  85     my $cwd = cwd();</pre>
  86 </dd>
  87 <dd>
  88 <p>The <a href="#item_cwd"><code>cwd()</code></a> is the most natural form for the current architecture. For
  89 most systems it is identical to `pwd` (but without the trailing line
  90 terminator).</p>
  91 </dd>
  92 <dt><strong><a name="item_fastcwd">fastcwd</a></strong>
  93
  94 <dd>
  95 <pre>
  96     my $cwd = fastcwd();</pre>
  97 </dd>
  98 <dd>
  99 <p>A more dangerous version of getcwd(), but potentially faster.</p>
 100 </dd>
 101 <dd>
 102 <p>It might conceivably <a href="file://C|\msysgit\mingw\html/pod/perlfunc.html#item_chdir"><code>chdir()</code></a> you out of a directory that it can't
 103 <a href="file://C|\msysgit\mingw\html/pod/perlfunc.html#item_chdir"><code>chdir()</code></a> you back into.  If fastcwd encounters a problem it will return
 104 undef but will probably leave you in a different directory.  For a
 105 measure of extra security, if everything appears to have worked, the
 106 <a href="#item_fastcwd"><code>fastcwd()</code></a> function will check that it leaves you in the same directory
 107 that it started in. If it has changed it will <code>die</code> with the message
 108 ``Unstable directory path, current directory changed
 109 unexpectedly''. That should never happen.</p>
 110 </dd>
 111 <dt><strong><a name="item_fastgetcwd">fastgetcwd</a></strong>
 112
 113 <dd>
 114 <pre>
 115   my $cwd = fastgetcwd();</pre>
 116 </dd>
 117 <dd>
 118 <p>The <a href="#item_fastgetcwd"><code>fastgetcwd()</code></a> function is provided as a synonym for cwd().</p>
 119 </dd>
 120 <dt><strong><a name="item_getdcwd">getdcwd</a></strong>
 121
 122 <dd>
 123 <pre>
 124     my $cwd = getdcwd();
 125     my $cwd = getdcwd('C:');</pre>
 126 </dd>
 127 <dd>
 128 <p>The <a href="#item_getdcwd"><code>getdcwd()</code></a> function is also provided on Win32 to get the current working
 129 directory on the specified drive, since Windows maintains a separate current
 130 working directory for each drive.  If no drive is specified then the current
 131 drive is assumed.</p>
 132 </dd>
 133 <dd>
 134 <p>This function simply calls the Microsoft C library <code>_getdcwd()</code> function.</p>
 135 </dd>
 136 </dl>
 137 <p>
 138 </p>
 139 <h2><a name="abs_path_and_friends">abs_path and friends</a></h2>
 140 <p>These functions are exported only on request.  They each take a single
 141 argument and return the absolute pathname for it.  If no argument is
 142 given they'll use the current working directory.</p>
 143 <dl>
 144 <dt><strong><a name="item_abs_path">abs_path</a></strong>
 145
 146 <dd>
 147 <pre>
 148   my $abs_path = abs_path($file);</pre>
 149 </dd>
 150 <dd>
 151 <p>Uses the same algorithm as getcwd().  Symbolic links and relative-path
 152 components (``.'' and ``..'') are resolved to return the canonical
 153 pathname, just like realpath(3).</p>
 154 </dd>
 155 <dt><strong><a name="item_realpath">realpath</a></strong>
 156
 157 <dd>
 158 <pre>
 159   my $abs_path = realpath($file);</pre>
 160 </dd>
 161 <dd>
 162 <p>A synonym for abs_path().</p>
 163 </dd>
 164 <dt><strong><a name="item_fast_abs_path">fast_abs_path</a></strong>
 165
 166 <dd>
 167 <pre>
 168   my $abs_path = fast_abs_path($file);</pre>
 169 </dd>
 170 <dd>
 171 <p>A more dangerous, but potentially faster version of abs_path.</p>
 172 </dd>
 173 </dl>
 174 <p>
 175 </p>
 176 <h2><a name="_env_pwd_">$ENV{PWD}</a></h2>
 177 <p>If you ask to override your <a href="file://C|\msysgit\mingw\html/pod/perlfunc.html#item_chdir"><code>chdir()</code></a> built-in function,</p>
 178 <pre>
 179   use Cwd qw(chdir);</pre>
 180 <p>then your PWD environment variable will be kept up to date.  Note that
 181 it will only be kept up to date if all packages which use chdir import
 182 it from Cwd.</p>
 183 <p>
 184 </p>
 185 <hr />
 186 <h1><a name="notes">NOTES</a></h1>
 187 <ul>
 188 <li>
 189 <p>Since the path seperators are different on some operating systems ('/'
 190 on Unix, ':' on MacPerl, etc...) we recommend you use the File::Spec
 191 modules wherever portability is a concern.</p>
 192 </li>
 193 <li>
 194 <p>Actually, on Mac OS, the <a href="#item_getcwd"><code>getcwd()</code></a>, <a href="#item_fastgetcwd"><code>fastgetcwd()</code></a> and <a href="#item_fastcwd"><code>fastcwd()</code></a>
 195 functions  are all aliases for the <a href="#item_cwd"><code>cwd()</code></a> function, which, on Mac OS,
 196 calls `pwd`. Likewise, the <a href="#item_abs_path"><code>abs_path()</code></a> function is an alias for
 197 <a href="#item_fast_abs_path"><code>fast_abs_path()</code></a>.</p>
 198 </li>
 199 </ul>
 200 <p>
 201 </p>
 202 <hr />
 203 <h1><a name="author">AUTHOR</a></h1>
 204 <p>Originally by the perl5-porters.</p>
 205 <p>Maintained by Ken Williams &lt;<a href="mailto:KWILLIAMS@cpan.org">KWILLIAMS@cpan.org</a>&gt;</p>
 206 <p>
 207 </p>
 208 <hr />
 209 <h1><a name="copyright">COPYRIGHT</a></h1>
 210 <p>Copyright (c) 2004 by the Perl 5 Porters.  All rights reserved.</p>
 211 <p>This program is free software; you can redistribute it and/or modify
 212 it under the same terms as Perl itself.</p>
 213 <p>Portions of the C code in this library are copyright (c) 1994 by the
 214 Regents of the University of California.  All rights reserved.  The
 215 license on this code is compatible with the licensing of the rest of
 216 the distribution - please see the source code in <em>Cwd.xs</em> for the
 217 details.</p>
 218 <p>
 219 </p>
 220 <hr />
 221 <h1><a name="see_also">SEE ALSO</a></h1>
 222 <p><a href="file://C|\msysgit\mingw\html/File/chdir.html">the File::chdir manpage</a></p>
 223 <table border="0" width="100%" cellspacing="0" cellpadding="3">
 224 <tr><td class="block" style="background-color: #cccccc" valign="middle">
 225 <big><strong><span class="block">&nbsp;Cwd - get pathname of current working directory</span></strong></big>
 226 </td></tr>
 227 </table>
 228
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