What debugging techniques can be used to troubleshoot issues with PHP code for reading and processing emails from a POP3 address?

Issue: When reading and processing emails from a POP3 address in PHP, it is important to properly handle errors and debug any issues that may arise. One common debugging technique is to use error reporting functions like error_reporting() and ini_set('display_errors', 1) to display any errors that occur during the script execution. Additionally, using logging functions like error_log() can help track the flow of the script and identify any potential issues with reading or processing emails. Finally, using var_dump() or print_r() to inspect variables and data structures can provide valuable insights into the state of the script at different points in the execution.

// Enable error reporting and display errors
error_reporting(E_ALL);
ini_set('display_errors', 1);

// Connect to the POP3 server and retrieve emails
$pop3 = new Net_POP3();
$pop3->connect('pop3.example.com', 110);
$pop3->login('username', 'password');

// Check for any errors during connection and login
if ($pop3->hasError()) {
    error_log('POP3 Error: ' . $pop3->lastError());
}

// Retrieve emails and process them
$emails = $pop3->listMessages();
foreach ($emails as $emailId) {
    $email = $pop3->getMessages($emailId);
    
    // Process the email content
    // ...
}

// Close the connection to the POP3 server
$pop3->disconnect();