PHP error handling

Last update on August 19 2022 21:50:39 (UTC/GMT +8 hours)

Description

PHP has a number of functions for handling as well as reporting errors. Besides, you can define your own way of handling and reporting errors. In this and subsequent pages we are going to discuss installation, runtime configuration, predefined constants and functions relating to PHP error handling and reporting.

Installation and configuration

In PHP 5, you don't need any external library, and you don't need any installation in addition to error handling and reporting.

Configuration settings for PHP Error handling and reporting are available in php.ini file, which is located in the php installation folder of your system.
Following is a list of error handling settings, there descriptions, default value and where they can be changed (Changeable).

For reference, settings of any PHP configuration can be changed in various ways - using ini_set(), in WINDOWS registry, in php.ini, in .htaccess or in httpd.conf. PHP_INI_ALL refers that the related configuration can be changed in any the aforementioned ways. PHP_INI_SYSTEM refers the entry can be set in php.ini or httpd.conf.

Name	Type	Description	Default	Changeable
error_reporting	integer	Set the error reporting level.	NULL	PHP_INI_ALL
display_errors	string	Determines if errors are displayed or hidden.	"1"	PHP_INI_ALL
display_startup_errors	boolean	Even if display_errors is on, hides errors that occur during PHP's startup sequence. Keep it off when online.	"0"	PHP_INI_ALL
log_errors	boolean	Specifies if script error messages should be logged to the server's error log.	"0"	PHP_INI_ALL
log_errors_max_len	integer	Specifies the maximum length of log_errors in bytes.	"1024"	PHP_INI_ALL
ignore_repeated_errors	boolean	Do not log repeated messages.	"0"	PHP_INI_ALL
ignore_repeated_source	boolean	Ignore source of message when ignoring repeated messages.	"0"	PHP_INI_ALL
report_memleaks	boolean	If set to Off, memory leaks (the program is unable to release memory it has occupied) will not be displayed.	"1"	PHP_INI_ALL
track_errors	boolean	If enabled, variable $php_errormsg will always hold the last error message.	"0"	PHP_INI_ALL
html_errors	boolean	Turns HTML tags off in error messages.	"1"	PHP_INI_ALL
xmlrpc_errors	boolean	Formats errors as XML-RPC error message, turning normal error reporting off.	"0"	PHP_INI_SYSTEM
xmlrpc_error_number	integer	Used as the value of the XML-RPC fault Code element.	"0"	PHP_INI_ALL
docref_root	string	Format of a new error which contains a reference to a page describing the error or function causing the error.	""	PHP_INI_ALL
docref_ext	string	Specifies the file extension of the reference page (as mentioned in docref_root).	""	PHP_INI_ALL
error_prepend_string	string	String to output before an error message.	NULL	PHP_INI_ALL
error_append_string	string	String to output after an error message.	NULL	PHP_INI_ALL
error_log	string	Name of the file where script errors should be logged.	NULL	PHP_INI_ALL

PHP error handling - predefined constants

Description

List of predefined constants used in PHP 5 for error handling.

Predefined constants

Here is a list of the predefined constants used in PHP 5 for error handling :

Name	Type	Description	value
E_ERROR	integer	Execution of the script comes to a halt. An example is memory allocation problem.	1
E_WARNING	integer	Execution of the script is not halted, warnings generated.	2
E_PARSE	integer	Parse errors generated by parsers during compilation.	4
E_NOTICE	integer	Run-time notices which indicated that may be an error took place but may also be a normal course of action.	8
E_CORE_ERROR	integer	Fatal errors that occur during the initial startup of PHP.	16
E_CORE_WARNING	integer	Warnings (execution of the script is not halted) that occur during PHP's initial startup.	32
E_COMPILE_ERROR	integer	Fatal compile-time errors.	64
E_COMPILE_WARNING	integer	Compile-time warnings, execution of the script is not halted.	128
E_USER_ERROR	integer	User-generated error message.	256
E_USER_WARNING	integer	User-generated warning message.	512
E_USER_NOTICE	integer	Same as E_NOTICE. The only difference is, trigger_error() function is used here to generate the error message.	1024
E_STRICT	integer	User-generated notice message.	2048
E_RECOVERABLE_ERROR	integer	Catchable fatal error.	4096
E_DEPRECATED	integer	Run-time notices.	8192
E_USER_DEPRECATED	integer	User-generated warning message.	16384
E_ALL	integer	All errors and warnings, as supported. Exception level `E_STRICT`.	30719

All these constants are available in php.ini of your PHP installation folder.

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