PHP and MySQL Web Development 4th Ed-tqw-_darksiderg

562 Chapter 26 Debugging
Error Reporting Levels
PHP allows you to set how fussy it should be with errors.You can modify what types of
events generate messages. By default, PHP reports all errors other than notices.
The error reporting level is assigned using a set of predefined constants, shown in
Table 26.1.
Table 26.1 Error Reporting Constants
Value Name Meaning
1 E_ERROR Report fatal errors at runtime
2 E_WARNING Report nonfatal errors at runtime
4 E_PARSE Report parse errors
8 E_NOTICE Report notices, notifications that something you have
done might be an error
16 E_CORE_ERROR Report failures in the startup of the PHP engine
32 E_CORE_WARNING Report nonfatal failures during the startup of the PHP
engine
64 E_COMPILE_ERROR Report errors in compilation
128 E_COMPILE_WARNING Report nonfatal errors in compilation
256 E_USER_ERROR Report user-triggered errors
512 E_USER_WARNING Report user-triggered warnings
1024 E_USER_NOTICE Report user-triggered notices
6143 E_ALL Report all errors and warnings except those reported in
E_STRICT
2048 E_STRICT Reports use of deprecated and unrecommended behavior;
not included in E_ALL but very useful for code
refactoring. Suggests changes for interoperability.
4096 E_RECOVERABLE_ERROR Reports catchable fatal errors.
Each constant represents a type of error that can be reported or ignored. If, for instance,
you specify the error level as E_ERROR, only fatal errors will be reported.These constants
can be combined using binary arithmetic, to produce different error levels.
The default error level—report all errors other than notices—is specified as follows:
E_ALL & ~E_NOTICE
This expression consists of two of the predefined constants combined using bitwise
arithmetic operators.The ampersand (&) is the bitwise AND operator and the tilde (~) is
the bitwise NOT operator.This expression can be read as E_ALL AND NOT E_NOTICE.
E_ALL itself is effectively a combination of all the other error types except for
E_STRICT. It could be replaced by the other levels combined together using the bitwise
OR operator (|):