1<?php 2include_once __DIR__ . '/../../include/shared-manual.inc'; 3$TOC = array(); 4$PARENTS = array(); 5include_once __DIR__ ."/toc/langref.inc"; 6$setup = array ( 7 'home' => 8 array ( 9 0 => 'index.php', 10 1 => 'PHP Manual', 11 ), 12 'head' => 13 array ( 14 0 => 'UTF-8', 15 1 => 'en', 16 ), 17 'this' => 18 array ( 19 0 => 'language.exceptions.php', 20 1 => 'Exceptions', 21 ), 22 'up' => 23 array ( 24 0 => 'langref.php', 25 1 => 'Language Reference', 26 ), 27 'prev' => 28 array ( 29 0 => 'language.namespaces.faq.php', 30 1 => 'FAQ: things you need to know about namespaces', 31 ), 32 'next' => 33 array ( 34 0 => 'language.exceptions.extending.php', 35 1 => 'Extending Exceptions', 36 ), 37 'alternatives' => 38 array ( 39 ), 40 'extra_header_links' => 41 array ( 42 'rel' => 'alternate', 43 'href' => '/manual/en/feeds/language.exceptions.atom', 44 'type' => 'application/atom+xml', 45 ), 46); 47$setup["toc"] = $TOC; 48$setup["parents"] = $PARENTS; 49manual_setup($setup); 50 51?> 52<div id="language.exceptions" class="chapter"> 53 <h1>Exceptions</h1> 54<h2>Table of Contents</h2><ul class="chunklist chunklist_chapter"><li><a href="language.exceptions.extending.php">Extending Exceptions</a></li></ul> 55 56 57 <p class="para"> 58 PHP 5 has an exception model similar to that of other programming languages. 59 An exception can be <em>throw</em>n, and caught 60 ("<em>catch</em>ed") within PHP. Code may be surrounded in a 61 <em>try</em> block, to facilitate the catching of potential 62 exceptions. Each <em>try</em> must have at least one 63 corresponding <em>catch</em> block. Multiple 64 <em>catch</em> blocks can be used to catch different classes of 65 exceptions. Normal execution (when no exception is thrown within the 66 <em>try</em> block, or when a <em>catch</em> matching 67 the thrown exception's class is not present) will continue after that last 68 <em>catch</em> block defined in sequence. Exceptions can be 69 <em>throw</em>n (or re-thrown) within a <em>catch</em> block. 70 </p> 71 <p class="para"> 72 When an exception is thrown, code following the statement will not be 73 executed, and PHP will attempt to find the first matching 74 <em>catch</em> block. If an 75 exception is not caught, a PHP Fatal Error will be issued with an 76 "<em>Uncaught Exception ...</em>" message, unless a handler has 77 been defined with <span class="function"><a href="function.set-exception-handler.php" class="function">set_exception_handler()</a></span>. 78 </p> 79 <p class="para"> 80 In PHP 5.5 and later, a <em>finally</em> block may also be 81 specified after the <em>catch</em> blocks. Code within the 82 <em>finally</em> block will always be executed after the 83 <em>try</em> and <em>catch</em> blocks, regardless of 84 whether an exception has been thrown, and before normal execution resumes. 85 </p> 86 <p class="para"> 87 The thrown object must be an instance of the <a href="class.exception.php" class="classname">Exception</a> 88 class or a subclass of <a href="class.exception.php" class="classname">Exception</a>. Trying to throw an 89 object that is not will result in a PHP Fatal Error. 90 </p> 91 <blockquote class="note"><p><strong class="note">Note</strong>: 92 <p class="para"> 93 Internal PHP functions mainly use 94 <a href="errorfunc.configuration.php#ini.error-reporting" class="link">Error reporting</a>, only modern 95 <a href="language.oop5.php" class="link">Object oriented</a> 96 extensions use exceptions. However, errors can be simply translated to 97 exceptions with <a href="class.errorexception.php" class="link">ErrorException</a>. 98 </p> 99 </p></blockquote> 100 <div class="tip"><strong class="tip">Tip</strong> 101 <p class="para"> 102 The <a href="intro.spl.php" class="link">Standard PHP Library (SPL)</a> provides a 103 good number of <a href="spl.exceptions.php" class="link">built-in exceptions</a>. 104 </p> 105 </div> 106 <div class="example" id="example-269"> 107 <p><strong>Example #1 Throwing an Exception</strong></p> 108 <div class="example-contents"> 109<div class="phpcode"><code><span style="color: #000000"> 110<span style="color: #0000BB"><?php<br></span><span style="color: #007700">function </span><span style="color: #0000BB">inverse</span><span style="color: #007700">(</span><span style="color: #0000BB">$x</span><span style="color: #007700">) {<br> if (!</span><span style="color: #0000BB">$x</span><span style="color: #007700">) {<br> throw new </span><span style="color: #0000BB">Exception</span><span style="color: #007700">(</span><span style="color: #DD0000">'Division by zero.'</span><span style="color: #007700">);<br> }<br> return </span><span style="color: #0000BB">1</span><span style="color: #007700">/</span><span style="color: #0000BB">$x</span><span style="color: #007700">;<br>}<br><br>try {<br> echo </span><span style="color: #0000BB">inverse</span><span style="color: #007700">(</span><span style="color: #0000BB">5</span><span style="color: #007700">) . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br> echo </span><span style="color: #0000BB">inverse</span><span style="color: #007700">(</span><span style="color: #0000BB">0</span><span style="color: #007700">) . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br>} catch (</span><span style="color: #0000BB">Exception $e</span><span style="color: #007700">) {<br> echo </span><span style="color: #DD0000">'Caught exception: '</span><span style="color: #007700">, </span><span style="color: #0000BB">$e</span><span style="color: #007700">-></span><span style="color: #0000BB">getMessage</span><span style="color: #007700">(), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br>}<br><br></span><span style="color: #FF8000">// Continue execution<br></span><span style="color: #007700">echo </span><span style="color: #DD0000">"Hello World\n"</span><span style="color: #007700">;<br></span><span style="color: #0000BB">?></span> 111</span> 112</code></div> 113 </div> 114 115 <div class="example-contents"><p>The above example will output:</p></div> 116 <div class="example-contents screen"> 117<div class="cdata"><pre> 1180.2 119Caught exception: Division by zero. 120Hello World 121</pre></div> 122 </div> 123 </div> 124 <div class="example" id="example-270"> 125 <p><strong>Example #2 Exception handling with a <em>finally</em> block</strong></p> 126 <div class="example-contents"> 127<div class="phpcode"><code><span style="color: #000000"> 128<span style="color: #0000BB"><?php<br></span><span style="color: #007700">function </span><span style="color: #0000BB">inverse</span><span style="color: #007700">(</span><span style="color: #0000BB">$x</span><span style="color: #007700">) {<br> if (!</span><span style="color: #0000BB">$x</span><span style="color: #007700">) {<br> throw new </span><span style="color: #0000BB">Exception</span><span style="color: #007700">(</span><span style="color: #DD0000">'Division by zero.'</span><span style="color: #007700">);<br> }<br> return </span><span style="color: #0000BB">1</span><span style="color: #007700">/</span><span style="color: #0000BB">$x</span><span style="color: #007700">;<br>}<br><br>try {<br> echo </span><span style="color: #0000BB">inverse</span><span style="color: #007700">(</span><span style="color: #0000BB">5</span><span style="color: #007700">) . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br>} catch (</span><span style="color: #0000BB">Exception $e</span><span style="color: #007700">) {<br> echo </span><span style="color: #DD0000">'Caught exception: '</span><span style="color: #007700">, </span><span style="color: #0000BB">$e</span><span style="color: #007700">-></span><span style="color: #0000BB">getMessage</span><span style="color: #007700">(), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br>} </span><span style="color: #0000BB">finally </span><span style="color: #007700">{<br> echo </span><span style="color: #DD0000">"First finally.\n"</span><span style="color: #007700">;<br>}<br><br>try {<br> echo </span><span style="color: #0000BB">inverse</span><span style="color: #007700">(</span><span style="color: #0000BB">0</span><span style="color: #007700">) . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br>} catch (</span><span style="color: #0000BB">Exception $e</span><span style="color: #007700">) {<br> echo </span><span style="color: #DD0000">'Caught exception: '</span><span style="color: #007700">, </span><span style="color: #0000BB">$e</span><span style="color: #007700">-></span><span style="color: #0000BB">getMessage</span><span style="color: #007700">(), </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br>} </span><span style="color: #0000BB">finally </span><span style="color: #007700">{<br> echo </span><span style="color: #DD0000">"Second finally.\n"</span><span style="color: #007700">;<br>}<br><br></span><span style="color: #FF8000">// Continue execution<br></span><span style="color: #007700">echo </span><span style="color: #DD0000">"Hello World\n"</span><span style="color: #007700">;<br></span><span style="color: #0000BB">?></span> 129</span> 130</code></div> 131 </div> 132 133 <div class="example-contents"><p>The above example will output:</p></div> 134 <div class="example-contents screen"> 135<div class="cdata"><pre> 1360.2 137First finally. 138Caught exception: Division by zero. 139Second finally. 140Hello World 141</pre></div> 142 </div> 143 </div> 144 <div class="example" id="example-271"> 145 <p><strong>Example #3 Nested Exception</strong></p> 146 <div class="example-contents"> 147<div class="phpcode"><code><span style="color: #000000"> 148<span style="color: #0000BB"><?php<br><br></span><span style="color: #007700">class </span><span style="color: #0000BB">MyException </span><span style="color: #007700">extends </span><span style="color: #0000BB">Exception </span><span style="color: #007700">{ }<br><br>class </span><span style="color: #0000BB">Test </span><span style="color: #007700">{<br> public function </span><span style="color: #0000BB">testing</span><span style="color: #007700">() {<br> try {<br> try {<br> throw new </span><span style="color: #0000BB">MyException</span><span style="color: #007700">(</span><span style="color: #DD0000">'foo!'</span><span style="color: #007700">);<br> } catch (</span><span style="color: #0000BB">MyException $e</span><span style="color: #007700">) {<br> </span><span style="color: #FF8000">// rethrow it<br> </span><span style="color: #007700">throw </span><span style="color: #0000BB">$e</span><span style="color: #007700">;<br> }<br> } catch (</span><span style="color: #0000BB">Exception $e</span><span style="color: #007700">) {<br> </span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$e</span><span style="color: #007700">-></span><span style="color: #0000BB">getMessage</span><span style="color: #007700">());<br> }<br> }<br>}<br><br></span><span style="color: #0000BB">$foo </span><span style="color: #007700">= new </span><span style="color: #0000BB">Test</span><span style="color: #007700">;<br></span><span style="color: #0000BB">$foo</span><span style="color: #007700">-></span><span style="color: #0000BB">testing</span><span style="color: #007700">();<br><br></span><span style="color: #0000BB">?></span> 149</span> 150</code></div> 151 </div> 152 153 <div class="example-contents"><p>The above example will output:</p></div> 154 <div class="example-contents screen"> 155<div class="cdata"><pre> 156string(4) "foo!" 157</pre></div> 158 </div> 159 </div> 160 161 162 163 </div> 164<?php manual_footer(); ?> 165
