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Derek Allardd2df9bc2007-04-15 17:41:17 +00005<title>CodeIgniter User Guide</title>
adminb0dd10f2006-08-25 17:25:49 +00006
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24<meta name='author' content='Rick Ellis' />
Derek Allardd2df9bc2007-04-15 17:41:17 +000025<meta name='description' content='CodeIgniter User Guide' />
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Derek Allardd2df9bc2007-04-15 17:41:17 +000036<td><h1>CodeIgniter User Guide Version 1.5.3</h1></td>
adminc0d5d522006-10-30 19:40:35 +000037<td id="breadcrumb_right"><a href="../toc.html">Table of Contents Page</a></td>
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Derek Allardd2df9bc2007-04-15 17:41:17 +000048<a href="http://www.codeigniter.com/">CodeIgniter Home</a> &nbsp;&#8250;&nbsp;
adminb0dd10f2006-08-25 17:25:49 +000049<a href="../index.html">User Guide Home</a> &nbsp;&#8250;&nbsp;
50Error Handling
51</td>
Derek Allardbc030912007-06-24 18:25:29 +000052<td id="searchbox"><form method="get" action="http://www.google.com/search"><input type="hidden" name="as_sitesearch" id="as_sitesearch" value="codeigniter.com/user_guide/" />Search User Guide&nbsp; <input type="text" class="input" style="width:200px;" name="q" id="q" size="31" maxlength="255" value="" />&nbsp;<input type="submit" class="submit" name="sa" value="Go" /></form></td>
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62
63<h1>Error Handling</h1>
64
Derek Allardd2df9bc2007-04-15 17:41:17 +000065<p>CodeIgniter lets you build error reporting into your applications using the functions described below.
adminb0dd10f2006-08-25 17:25:49 +000066In addition, it has an error logging class that permits error and debugging messages to be saved as text files.</p>
67
Derek Allardd2df9bc2007-04-15 17:41:17 +000068<p class="important"><strong>Note:</strong> By default, CodeIgniter displays all PHP errors. You might
adminb0dd10f2006-08-25 17:25:49 +000069wish to change this behavior once your development is complete. You'll find the <dfn>error_reporting()</dfn>
70function located at the top of your main index.php file. Disabling error reporting will NOT prevent log files
71from being written if there are errors.</p>
72
Derek Allardd2df9bc2007-04-15 17:41:17 +000073<p>Unlike most systems in CodeIgniter, the error functions are simple procedural interfaces that are available
adminb0dd10f2006-08-25 17:25:49 +000074globally throughout the application. This approach permits error messages to get triggered without having to worry
75about class/function scoping.</p>
76
77<p>The following functions let you generate errors:</p>
78
79<h2>show_error('<var>message</var>')</h2>
80<p>This function will display the error message supplied to it using the following error template:</p>
81<p><dfn>application/errors/</dfn><kbd>error_general.php</kbd></p>
82
83<h2>show_404('<var>page</var>')</h2>
84<p>This function will display the 404 error message supplied to it using the following error template:</p>
85<p><dfn>application/errors/</dfn><kbd>error_404.php</kbd></p>
86
87<p>The function expects the string passed to it to be the file path to the page that isn't found.
Derek Allardd2df9bc2007-04-15 17:41:17 +000088Note that CodeIgniter automatically shows 404 messages if controllers are not found.</p>
adminb0dd10f2006-08-25 17:25:49 +000089
90
91<h2>log_message('<var>level</var>', '<samp>message</samp>')</h2>
92
admine334c472006-10-21 19:44:22 +000093<p>This function lets you write messages to your log files. You must supply one of three "levels"
adminb0dd10f2006-08-25 17:25:49 +000094in the first parameter, indicating what type of message it is (debug, error, info), with the message
95itself in the second parameter. Example:</p>
96
97<code>
98if ($some_var == "")<br />
99{<br />
100&nbsp;&nbsp;&nbsp;&nbsp;log_message('error', 'Some variable did not contain a value.');<br />
101}<br />
102else<br />
103{<br />
104&nbsp;&nbsp;&nbsp;&nbsp;log_message('debug', 'Some variable was correctly set');<br />
105}<br />
106<br />
107log_message('info', 'The purpose of some variable is to provide some value.');<br />
108</code>
109
110<p>There are three message types:</p>
111
112<ol>
113<li>Error Messages. These are actual errors, such as PHP errors or user errors.</li>
114<li>Debug Messages. These are messages that assist in debugging. For example, if a class has been initialized, you could log this as debugging info.</li>
Derek Allardd2df9bc2007-04-15 17:41:17 +0000115<li>Informational Messages. These are the lowest priority messages, simply giving information regarding some process. CodeIgniter doesn't natively generate any info messages but you may want to in your application.</li>
adminb0dd10f2006-08-25 17:25:49 +0000116</ol>
117
118
admine334c472006-10-21 19:44:22 +0000119<p class="important"><strong>Note:</strong> In order for the log file to actually be written, the
120 "logs" folder must be writable. In addition, you must set the "threshold" for logging.
adminb06d69f2006-10-13 21:44:17 +0000121You might, for example, only want error messages to be logged, and not the other two types.
122If you set it to zero logging will be disabled.</p>
adminb0dd10f2006-08-25 17:25:49 +0000123
124
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Derek Allardc6441282007-07-04 23:54:32 +0000137</p>
Derek Allardd2df9bc2007-04-15 17:41:17 +0000138<p><a href="http://www.codeigniter.com">CodeIgniter</a> &nbsp;&middot;&nbsp; Copyright &#169; 2007 &nbsp;&middot;&nbsp; <a href="http://ellislab.com/">Ellislab, Inc.</a></p>
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