How can PHP developers ensure that their code functions consistently across different server environments?

PHP developers can ensure their code functions consistently across different server environments by using PHP configuration settings to set the environment variables, error reporting, and other settings consistently. They can also use PHP version checks and feature detection to ensure compatibility with different PHP versions. Additionally, using a PHP framework or library that abstracts away server-specific details can help maintain consistency across environments.

// Set environment variables consistently
putenv('ENVIRONMENT=production');

// Set error reporting level consistently
error_reporting(E_ALL);

// Check PHP version and features for compatibility
if (version_compare(PHP_VERSION, '7.0.0', '<')) {
    // Code for PHP 5.x compatibility
} else {
    // Code for PHP 7.x and above
}

// Use a PHP framework or library to abstract server-specific details
// Example with Laravel framework
// $app->environment('production');