These are functions dealing with error handling and logging. They allow you to define your own error handling rules, as well as modify the way the errors can be logged. This allows you to change and enhance error reporting to suit your needs.
With the logging functions, you can send messages directly to other machines, to an email (or email to pager gateway!), to system logs, etc., so you can selectively log and monitor the most important parts of your applications and websites.
The error reporting functions allow you to customize what level and kind of error feedback is given, ranging from simple notices to customized functions returned during errors.
These functions are available as part of the standard module, which is always available.
There is no installation needed to use these functions, they are part of the PHP core.
These constants are part of the PHP core and always available.
Table 1. Errors and Logging
| Value | Constant | Description |
|---|---|---|
| 1 | E_ERROR (integer) | Fatal run-time errors. These indicate errors that can not be recovered from, such as a memory allocation problem. Execution of the script is halted. |
| 2 | E_WARNING (integer) | Run-time warnings (non-fatal errors). Execution of the script is not halted. |
| 4 | E_PARSE (integer) | Compile-time parse errors. Parse errors should only be generated by the parser. |
| 8 | E_NOTICE (integer) | Run-time notices. Indicate that the script encountered something that could indicate an error, but could also happen in the normal course of running a script. |
| 16 | E_CORE_ERROR (integer) | Fatal errors that occur during PHP's initial startup. This is like an E_ERROR, except it is generated by the core of PHP. |
| 32 | E_CORE_WARNING (integer) | Warnings (non-fatal errors) that occur during PHP's initial startup. This is like an E_WARNING, except it is generated by the core of PHP. PHP 4 only. |
| 64 | E_COMPILE_ERROR (integer) | Fatal compile-time errors. This is like an E_ERROR, except it is generated by the Zend Scripting Engine. PHP 4 only. |
| 128 | E_COMPILE_WARNING (integer) | Compile-time warnings (non-fatal errors). This is like an E_WARNING, except it is generated by the Zend Scripting Engine. PHP 4 only. |
| 256 | E_USER_ERROR (integer) | User-generated error message. This is like an E_ERROR, except it is generated in PHP code by using the PHP function trigger_error(). PHP 4 only. |
| 512 | E_USER_WARNING (integer) | User-generated warning message. This is like an E_WARNING, except it is generated in PHP code by using the PHP function trigger_error(). PHP 4 only. |
| 1024 | E_USER_NOTICE (integer) | User-generated notice message. This is like an E_NOTICE, except it is generated in PHP code by using the PHP function trigger_error(). PHP 4 only. |
| 2047 | E_ALL (integer) | All errors and warnings, as supported. |
Fore more Information see the section Error Handling.