PHP - Error & Logging Functions

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.

Using these logging functions, you can send messages directly to other machines, to an email, to system logs, etc., so you can selectively log and monitor the most important parts of your applications and websites.

Installation

The error and logging functions are part of the PHP core. There is no installation needed to use these functions.

Runtime Configuration

The behaviour of these functions is affected by settings in php.ini. These settings are defined below.

Name	Default	Changeable	Changelog
error_reporting	NULL	PHP_INI_ALL
display_errors	"1"	PHP_INI_ALL
display_startup_errors	"0"	PHP_INI_ALL	Available since PHP 4.0.3.
log_errors	"0"	PHP_INI_ALL
log_errors_max_len	"1024"	PHP_INI_ALL	Available since PHP 4.3.0.
ignore_repeated_errors	"0"	PHP_INI_ALL	Available since PHP 4.3.0.
ignore_repeated_source	"0"	PHP_INI_ALL	Available since PHP 4.3.0.
report_memleaks	"1"	PHP_INI_ALL	Available since PHP 4.3.0.
track_errors	"0"	PHP_INI_ALL
html_errors	"1"	PHP_INI_ALL	PHP_INI_SYSTEM in PHP <= 4.2.3. Available since PHP 4.0.2.
docref_root	""	PHP_INI_ALL	Available since PHP 4.3.0.
docref_ext	""	PHP_INI_ALL	Available since PHP 4.3.2.
error_prepend_string	NULL	PHP_INI_ALL
error_append_string	NULL	PHP_INI_ALL
error_log	NULL	PHP_INI_ALL
warn_plus_overloading	NULL		This option is no longer available as of PHP 4.0.0

PHP Error and Logging Constants

PHP − indicates the earliest version of PHP that supports the constant.

You can use any of the constant while configuring your php.ini file.

Value	Constant & Description	PHP
1	E_ERROR Fatal run-time errors. Errors that cannot be recovered from. Execution of the script is halted
2	E_WARNING Non-fatal run-time errors. Execution of the script is not halted
4	E_PARSE Compile-time parse errors. Parse errors should only be generated by the parser
8	E_NOTICE Run-time notices. The script found something that might be an error, but could also happen when running a script normally
16	E_CORE_ERROR Fatal errors at PHP startup. This is like an E_ERROR in the PHP core	4
32	E_CORE_WARNING Non-fatal errors at PHP startup. This is like an E_WARNING in the PHP core	4
64	E_COMPILE_ERROR Fatal compile-time errors. This is like an E_ERROR generated by the Zend Scripting Engine	4
128	E_COMPILE_WARNING Non-fatal compile-time errors. This is like an E_WARNING generated by the Zend Scripting Engine	4
256	E_USER_ERROR Fatal user-generated error. This is like an E_ERROR set by the programmer using the PHP function trigger_error()	4
512	E_USER_WARNING Non-fatal user-generated warning. This is like an E_WARNING set by the programmer using the PHP function trigger_error()	4
1024	E_USER_NOTICE User-generated notice. This is like an E_NOTICE set by the programmer using the PHP function trigger_error()	4
2048	E_STRICT Run-time notices. PHP suggest changes to your code to help interoperability and compatibility of the code	5
4096	E_RECOVERABLE_ERROR Catchable fatal error. This is like an E_ERROR but can be caught by a user defined handle (see also set_error_handler())	5
8191	E_ALL All errors and warnings, except of level E_STRICT	5

List of Functions

PHP − indicates the earliest version of PHP that supports the function.

Sr.No	Advanced & Description	PHP
1	debug_backtrace() Generates a backtrace	4
2	debug_print_backtrace() Prints a backtrace	5
3	error_get_last() Gets the last error occurred	5
4	error_log() Sends an error to the server error-log, to a file or to a remote destination	4
5	error_reporting() Specifies which errors are reported	4
6	restore_error_handler() Restores the previous error handler	4
7	restore_exception_handler() Restores the previous exception handler	5
8	set_error_handler() Sets a user-defined function to handle errors	4
9	set_exception_handler() Sets a user-defined function to handle exceptions	5
10	trigger_error() Creates a user-defined error message	4
11	user_error() Alias of trigger_error()	4

php_function_reference.htm