There are several types of errors and warnings in PHP. They are:
Table 15-1. PHP error types
| Value | Constant | Description | Note |
|---|
| 1 | E_ERROR | fatal run-time errors | |
| 2 | E_WARNING | run-time warnings (non fatal errors) | |
| 4 | E_PARSE | compile-time parse errors | |
| 8 | E_NOTICE |
run-time notices (less serious than warnings)
| |
| 16 | E_CORE_ERROR | fatal errors that occur during PHP's initial startup | PHP 4 only |
| 32 | E_CORE_WARNING |
warnings (non fatal errors) that occur during PHP's initial
startup
| PHP 4 only |
| 64 | E_COMPILE_ERROR | fatal compile-time errors | PHP 4 only |
| 128 | E_COMPILE_WARNING | compile-time warnings (non fatal errors) | PHP 4 only |
| 256 | E_USER_ERROR | user-generated error message | PHP 4 only |
| 512 | E_USER_WARNING | user-generated warning message | PHP 4 only |
| 1024 | E_USER_NOTICE | user-generated notice message | PHP 4 only |
| | E_ALL | all of the above, as supported | |
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, however, and that no bitwise
operators will be understood within php3.ini.
In PHP 4, the default error_reporting setting is
E_ALL & ~E_NOTICE, meaning to display all errors
and warnings which are not E_NOTICE-level. In PHP 3, the default
setting is (E_ERROR | E_WARNING | E_PARSE),
meaning the same thing. Note, however, that since constants are not
supported in PHP 3's php3.ini, the error_reporting setting there
must be numeric; hence, it is 7.
The initial setting can be changed in the ini file with the error_reporting directive, in
your Apache httpd.conf file with the
php_error_reporting (php3_error_reporting for PHP 3) directive, and
lastly it may be set at runtime within a script by using the
error_reporting() function.
| Warning |
When upgrading code or servers from PHP 3 to PHP 4 you should
check these settings and calls to
error_reporting() or you might disable
reporting the new error types, especially E_COMPILE_ERROR. This
may lead to empty documents without any feedback of what happened
or where to look for the problem.
|
All PHP expressions can
also be called with the "@" prefix, which turns off error reporting
for that particular expression. If an error occurred during such
an expression and the track_errors feature is enabled,
you can find the error message in the global variable
$php_errormsg.
| Warning |
Currently the @
error-control operator prefix will even disable error
reporting for critical errors that will terminate script
execution. Among other things, this means that if you use @ to suppress
errors from a certain function and either it isn't available or
has been mistyped, the script will die right there with no
indication as to why.
|
