set_error_handler
Sets a user-defined error handler function.
Descriptionstringset_error_handlercallbackerror_handler
Sets a user function (error_handler) to handle
errors in a script. Returns the previously defined error handler (if
any), or &false; on error. This function can be used for defining your own
way of handling errors during runtime, for example in applications in
which you need to do cleanup of data/files when a critical error happens,
or when you need to trigger an error under certain conditions (using
trigger_error).
The user function needs to accept two parameters: the error code, and a
string describing the error. From PHP 4.0.2, three optional
parameters are supplied: the filename in which the error occurred, the
line number in which the error occurred, and the context in which the
error occurred (an array that points to the active symbol table at the
point the error occurred).
Instead of a function name, an array containing an object reference and
a method name can also be supplied. (Since PHP 4.3.0)
The following error types cannot be handled with a user defined
function: E_ERROR, E_PARSE,
E_CORE_ERROR, E_CORE_WARNING,
E_COMPILE_ERROR and
E_COMPILE_WARNING.
The example below shows the handling of internal exceptions by
triggering errors and handling them with a user defined function:
Error handling with <function>set_error_handler</function> and
<function>trigger_error</function>
FATAL [$errno] $errstr \n";
echo " Fatal error in line $errline of file $errfile";
echo ", PHP ".PHP_VERSION." (".PHP_OS.") \n";
echo "Aborting... \n";
exit(1);
break;
case ERROR:
echo "ERROR [$errno] $errstr \n";
break;
case WARNING:
echo "WARNING [$errno] $errstr \n";
break;
default:
echo "Unkown error type: [$errno] $errstr \n";
break;
}
}
// function to test the error handling
function scale_by_log ($vect, $scale)
{
if (!is_numeric($scale) || $scale <= 0) {
trigger_error("log(x) for x <= 0 is undefined, you used: scale = $scale",
FATAL);
}
if (!is_array($vect)) {
trigger_error("Incorrect input vector, array of values expected", ERROR);
return null;
}
for ($i=0; $i
]]>
And when you run this sample script, the output will be :
2
[1] => 3
[2] => foo
[3] => 5.5
[4] => 43.3
[5] => 21.11
)
----
vector b - a warning (b = log(PI) * a)
WARNING [1024] Value at position 2 is not a number, using 0 (zero)
Array
(
[0] => 2.2894597716988
[1] => 3.4341896575482
[2] => 0
[3] => 6.2960143721717
[4] => 49.566804057279
[5] => 24.165247890281
)
----
vector c - an error
ERROR [512] Incorrect input vector, array of values expected
NULL
----
vector d - fatal error
FATAL [256] log(x) for x <= 0 is undefined, you used: scale = -2.5
Fatal error in line 36 of file trigger_error.php, PHP 4.0.2 (Linux)
Aborting...
]]>
It is important to remember that the standard PHP error handler is completely
bypassed. error_reporting settings will have no effect
and your error handler will be called regardless - however you are still
able to read the current value of error_reporting and
act appropriately. Of particular note is that this value will be 0 if the
statement that caused the error was prepended by the
@ error-control
operator.
Also note that it is your responsibility to die if
necessary. If the error-handler function returns, script execution
will continue with the next statement after the one that caused an error.
If errors occur before the script is executed (e.g. on file uploads) the custom
error handler cannot be called since it is not registered at that time.
See also error_reporting,
restore_error_handler,
trigger_error, user_error