Error Handling
PHP Manual

Predefined Constants

The constants below are always available as part of the PHP core.

Note: You may use these constant names in php.ini but not outside of PHP, like in httpd.conf, where you'd use the bitmask values instead.

Errors and Logging
Value Constant Description Note
1 E_ERROR (int) Fatal run-time errors. These indicate errors that can not be recovered from, such as a memory allocation problem. Execution of the script is halted.  
2 E_WARNING (int) Run-time warnings (non-fatal errors). Execution of the script is not halted.  
4 E_PARSE (int) Compile-time parse errors. Parse errors should only be generated by the parser.  
8 E_NOTICE (int) Run-time notices. Indicate that the script encountered something that could indicate an error, but could also happen in the normal course of running a script.  
16 E_CORE_ERROR (int) Fatal errors that occur during PHP's initial startup. This is like an E_ERROR, except it is generated by the core of PHP.  
32 E_CORE_WARNING (int) Warnings (non-fatal errors) that occur during PHP's initial startup. This is like an E_WARNING, except it is generated by the core of PHP.  
64 E_COMPILE_ERROR (int) Fatal compile-time errors. This is like an E_ERROR, except it is generated by the Zend Scripting Engine.  
128 E_COMPILE_WARNING (int) Compile-time warnings (non-fatal errors). This is like an E_WARNING, except it is generated by the Zend Scripting Engine.  
256 E_USER_ERROR (int) User-generated error message. This is like an E_ERROR, except it is generated in PHP code by using the PHP function trigger_error.  
512 E_USER_WARNING (int) User-generated warning message. This is like an E_WARNING, except it is generated in PHP code by using the PHP function trigger_error.  
1024 E_USER_NOTICE (int) User-generated notice message. This is like an E_NOTICE, except it is generated in PHP code by using the PHP function trigger_error.  
2048 E_STRICT (int) Enable to have PHP suggest changes to your code which will ensure the best interoperability and forward compatibility of your code.  
4096 E_RECOVERABLE_ERROR (int) Catchable fatal error. It indicates that a probably dangerous error occurred, but did not leave the Engine in an unstable state. If the error is not caught by a user defined handle (see also set_error_handler), the application aborts as it was an E_ERROR.  
8192 E_DEPRECATED (int) Run-time notices. Enable this to receive warnings about code that will not work in future versions.  
16384 E_USER_DEPRECATED (int) User-generated warning message. This is like an E_DEPRECATED, except it is generated in PHP code by using the PHP function trigger_error.  
32767 E_ALL (int) All errors, warnings, and notices.  

The above values (either numerical or symbolic) are used to build up a bitmask that specifies which errors to report. You can use the bitwise operators to combine these values or mask out certain types of errors. Note that only '|', '~', '!', '^' and '&' will be understood within php.ini.