mingw/html/lib/warnings.html

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   5 <title>warnings - Perl pragma to control optional warnings</title>
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  13 <big><strong><span class="block">&nbsp;warnings - Perl pragma to control optional warnings</span></strong></big>
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  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>
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  27
  28 <hr />
  29 <p>
  30 </p>
  31 <h1><a name="name">NAME</a></h1>
  32 <p>warnings - Perl pragma to control optional warnings</p>
  33 <p>
  34 </p>
  35 <hr />
  36 <h1><a name="synopsis">SYNOPSIS</a></h1>
  37 <pre>
  38     use warnings;
  39     no warnings;</pre>
  40 <pre>
  41     use warnings &quot;all&quot;;
  42     no warnings &quot;all&quot;;</pre>
  43 <pre>
  44     use warnings::register;
  45     if (warnings::enabled()) {
  46         warnings::warn(&quot;some warning&quot;);
  47     }</pre>
  48 <pre>
  49     if (warnings::enabled(&quot;void&quot;)) {
  50         warnings::warn(&quot;void&quot;, &quot;some warning&quot;);
  51     }</pre>
  52 <pre>
  53     if (warnings::enabled($object)) {
  54         warnings::warn($object, &quot;some warning&quot;);
  55     }</pre>
  56 <pre>
  57     warnings::warnif(&quot;some warning&quot;);
  58     warnings::warnif(&quot;void&quot;, &quot;some warning&quot;);
  59     warnings::warnif($object, &quot;some warning&quot;);</pre>
  60 <p>
  61 </p>
  62 <hr />
  63 <h1><a name="description">DESCRIPTION</a></h1>
  64 <p>The <code>warnings</code> pragma is a replacement for the command line flag <code>-w</code>,
  65 but the pragma is limited to the enclosing block, while the flag is global.
  66 See <a href="file://C|\msysgit\mingw\html/pod/perllexwarn.html">the perllexwarn manpage</a> for more information.</p>
  67 <p>If no import list is supplied, all possible warnings are either enabled
  68 or disabled.</p>
  69 <p>A number of functions are provided to assist module authors.</p>
  70 <dl>
  71 <dt><strong><a name="item_use_warnings_3a_3aregister">use warnings::register</a></strong>
  72
  73 <dd>
  74 <p>Creates a new warnings category with the same name as the package where
  75 the call to the pragma is used.</p>
  76 </dd>
  77 </li>
  78 <dt><strong><a name="item_enabled">warnings::enabled()</a></strong>
  79
  80 <dd>
  81 <p>Use the warnings category with the same name as the current package.</p>
  82 </dd>
  83 <dd>
  84 <p>Return TRUE if that warnings category is enabled in the calling module.
  85 Otherwise returns FALSE.</p>
  86 </dd>
  87 </li>
  88 <dt><strong>warnings::enabled($category)</strong>
  89
  90 <dd>
  91 <p>Return TRUE if the warnings category, <code>$category</code>, is enabled in the
  92 calling module.
  93 Otherwise returns FALSE.</p>
  94 </dd>
  95 </li>
  96 <dt><strong>warnings::enabled($object)</strong>
  97
  98 <dd>
  99 <p>Use the name of the class for the object reference, <code>$object</code>, as the
 100 warnings category.</p>
 101 </dd>
 102 <dd>
 103 <p>Return TRUE if that warnings category is enabled in the first scope
 104 where the object is used.
 105 Otherwise returns FALSE.</p>
 106 </dd>
 107 </li>
 108 <dt><strong><a name="item_warn">warnings::warn($message)</a></strong>
 109
 110 <dd>
 111 <p>Print <code>$message</code> to STDERR.</p>
 112 </dd>
 113 <dd>
 114 <p>Use the warnings category with the same name as the current package.</p>
 115 </dd>
 116 <dd>
 117 <p>If that warnings category has been set to ``FATAL'' in the calling module
 118 then die. Otherwise return.</p>
 119 </dd>
 120 </li>
 121 <dt><strong>warnings::warn($category, $message)</strong>
 122
 123 <dd>
 124 <p>Print <code>$message</code> to STDERR.</p>
 125 </dd>
 126 <dd>
 127 <p>If the warnings category, <code>$category</code>, has been set to ``FATAL'' in the
 128 calling module then die. Otherwise return.</p>
 129 </dd>
 130 </li>
 131 <dt><strong>warnings::warn($object, $message)</strong>
 132
 133 <dd>
 134 <p>Print <code>$message</code> to STDERR.</p>
 135 </dd>
 136 <dd>
 137 <p>Use the name of the class for the object reference, <code>$object</code>, as the
 138 warnings category.</p>
 139 </dd>
 140 <dd>
 141 <p>If that warnings category has been set to ``FATAL'' in the scope where <code>$object</code>
 142 is first used then die. Otherwise return.</p>
 143 </dd>
 144 </li>
 145 <dt><strong><a name="item_warnif">warnings::warnif($message)</a></strong>
 146
 147 <dd>
 148 <p>Equivalent to:</p>
 149 </dd>
 150 <dd>
 151 <pre>
 152     if (warnings::enabled())
 153       { warnings::warn($message) }</pre>
 154 </dd>
 155 </li>
 156 <dt><strong>warnings::warnif($category, $message)</strong>
 157
 158 <dd>
 159 <p>Equivalent to:</p>
 160 </dd>
 161 <dd>
 162 <pre>
 163     if (warnings::enabled($category))
 164       { warnings::warn($category, $message) }</pre>
 165 </dd>
 166 </li>
 167 <dt><strong>warnings::warnif($object, $message)</strong>
 168
 169 <dd>
 170 <p>Equivalent to:</p>
 171 </dd>
 172 <dd>
 173 <pre>
 174     if (warnings::enabled($object))
 175       { warnings::warn($object, $message) }</pre>
 176 </dd>
 177 </li>
 178 </dl>
 179 <p>See <a href="file://C|\msysgit\mingw\html/pod/perlmodlib.html#pragmatic_modules">Pragmatic Modules in the perlmodlib manpage</a> and <a href="file://C|\msysgit\mingw\html/pod/perllexwarn.html">the perllexwarn manpage</a>.</p>
 180 <table border="0" width="100%" cellspacing="0" cellpadding="3">
 181 <tr><td class="block" style="background-color: #cccccc" valign="middle">
 182 <big><strong><span class="block">&nbsp;warnings - Perl pragma to control optional warnings</span></strong></big>
 183 </td></tr>
 184 </table>
 185
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