Used to trigger a user error condition, it can be used by in conjunction with the built-in error handler, or with a user defined function that has been set as the new error handler (set_error_handler()). It only works with the E_USER family of constants, and will default to E_USER_NOTICE.
This function returns FALSE if wrong error_type is specified, TRUE otherwise.
This function is useful when you need to generate a particular response to an exception at runtime. For example:
Note: See set_error_handler() for a more extensive example.
Note: error_msg is limited to 1024 characters in length. Any additional characters beyond 1024 will be truncated.
See also error_reporting(), set_error_handler(), restore_error_handler(), and error level constants.