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 second parameter error_types was introduced in PHP 5 and 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.
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). 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, errfile, which contains the filename that the error was raised in, as a string.
The fourth parameter is optional, errline, which contains the line number the error was raised at, as an integer.
The fifth parameter is optional, errcontext, which is an array that points to the active symbol table at the point the error occurred. In other words, errcontext will contain an array of every variable that existed in the scope the error was triggered in.
Note: Instead of a function name, an array containing an object reference and a method name can also be supplied. (Since PHP 4.3.0)
Note: 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:
Example 1. Error handling with set_error_handler() and trigger_error()
And when you run this sample script, the output will be:
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.
Note: 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.
Note: The second parameter error_types was introduced in PHP 5.
|Sites of interest: Web Hosting : Reseller Hosting : Website Hosting : HTML Editor : Web Design Templates : Free Web Hosting : ASP code examples : PHP & MySQL Code Examples|