PHP - Error & Logging Functions


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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

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