Using Custom Error Handler

In PHP, you can define custom error handlers using the set_error_handler function. A custom error handler allows you to handle PHP errors in a way that suits your application, such as logging errors, displaying a custom error page, or taking specific actions based on the type of error.

Here's an example of how to use a custom error handler:

<?php
// Custom error handler function
function customErrorHandler($errno, $errstr, $errfile, $errline) {
    echo "<b>Error:</b> [$errno] $errstr<br>";
    echo "Error on line $errline in $errfile<br>";
}

// Set custom error handler
set_error_handler('customErrorHandler');

// Trigger an error (division by zero)
$number = 10 / 0;

// The following line will not be executed because the script terminates after the error
echo "This line will not be executed.";
?>

In this example:

1. The customErrorHandler function is defined. This function will be called when a PHP error occurs.

2. The set_error_handler function is used to set the custom error handler. It takes the name of the custom error handler function as an argument.

3. An error is triggered by attempting to perform a division by zero.

4. The custom error handler function is invoked, displaying information about the error.

5. Since the error handler includes an echo statement, the subsequent code after the error will not be executed.

Custom error handlers should be used with caution, and it's essential to consider the impact on the application. In a production environment, you might want to log errors to a file or database instead of displaying them directly to users. Additionally, you can customize the error handler function to handle different types of errors differently.

Remember to restore the default error handler after using a custom error handler, especially in scenarios where the error handling is specific to a certain section of code. You can use the restore_error_handler function for this purpose.

Thank you.