Sets a user function (
error_handler) to handle
errors in a script.
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()).
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.
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, E_COMPILE_WARNING, and most of E_STRICT raised in the file where set_error_handler() is called.
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.
The user function needs to accept two parameters: the error code, and a string describing the error. Then there are three optional parameters that may be 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). The function can be shown as:
handler ( int errno, string errstr [, string errfile [, int errline [, array errcontext]]] )
The first parameter,
errno, contains the
level of the error raised, as an integer.
The second parameter,
errstr, contains the
error message, as a string.
The third parameter is optional,
which contains the filename that the error was raised in, as a string.
The fourth parameter is optional,
which contains the line number the error was raised at, as an integer.
The fifth parameter is optional,
which is an array that points to the active symbol table at the point
the error occurred. In other words,
will contain an array of every variable that existed in the scope the
error was triggered in.
User error handler must not modify error context.
Can be used to mask the triggering of the
error_handler function just like the error_reporting ini setting
controls which errors are shown. Without this mask set the
error_handler will be called for every error
regardless to the setting of the error_reporting setting.
Returns a string containing the previously defined error handler (if any), or NULL on error. If the previous handler was a class method, this function will return an indexed array with the class and the method name.
|5.2.0||The error handler must return FALSE to populate $php_errormsg.|
Instead of a function name, an array containing an object reference
and a method name can also be supplied as the
Three optional parameters for the |
Example 1. Error handling with set_error_handler() and trigger_error()
The example below shows the handling of internal exceptions by triggering errors and handling them with a user defined function:
The above example will output something similar to:
|error level constants|
|information about the callback type|