An in-depth understanding of PHP error and logging functions _php instances

Introduction to PHP Error and logging
The error and logging functions allow you to manipulate and record errors.
The error function allows the user to define a rule for handling errors and to modify how errors are logged.
The logging function allows users to log applications and send log messages to e-mail, system logs, or other machines.

Installation
The error and logging functions are part of the PHP core. These functions can be used without installation.
PHP Error and Logging functions

PHP: Indicates the earliest version of PHP that supports this function.
Function Description PHP
Debug_backtrace () generates BackTrace. 4
Debug_print_backtrace () output backtrace. 5
Error_get_last () Gets the last error that occurred. 5
Error_log () sends an error to the server error record, file, or remote destination. 4
Error_reporting () specifies which error to report. 4
Restore_error_handler () Restores the previous error handler. 4
Restore_exception_handler () Restores the previous exception handler. 5
Set_error_handler () Sets the user-defined error-handling function. 4
Set_exception_handler () Sets the user-defined exception handling function. 5
Trigger_error () Creates a user-defined error message. 4
Alias of User_error () Trigger_error (). 4
PHP Error and Logging constants

PHP: Indicates the earliest version of PHP that supports this constant.
Value constants describe PHP
1 E_error Fatal Run-time error. The error cannot be recovered. Execution of the script was interrupted.
2 e_warning non-fatal run-time error. The execution of the script is not interrupted.
4 E_parse Compile-time syntax parsing error. Parsing errors should only be generated by the parser.
8 E_notice Run-time prompt. May be an error, or it may occur when the script is running normally.
E_core_error errors generated internally by PHP. 4
E_core_warning generated by PHP internal warning. 4
E_compile_error errors generated internally by the Zend scripting engine. 4
E_compile_warning a warning generated internally by the Zend scripting engine. 4
E_user_error because of a run-time error generated by calling the Trigger_error () function. 4
E_user_warning a run-time warning generated by calling the Trigger_error () function. 4
1024x768 E_user_notice The runtime prompt generated by calling the Trigger_error () function. 4
2048 e_strict run-time prompt. Benefit from enhanced code interoperability and compatibility. 5
4096 E_recoverable_error A fatal error that can be captured. (see Set_error_handler ()) 5
8191 E_all all errors and warnings except E_strict. 5

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