⚠️ PHP Error Handling – Detect, Control, and Manage Errors in PHP

Learn how to handle runtime errors in PHP using built-in error types, configurations, and reporting tools to create stable and secure applications.

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🧲 Introduction – Why PHP Error Handling Matters

Errors are a natural part of software development. PHP provides built-in support for reporting, logging, and managing errors of various severity levels. Understanding how PHP handles errors allows you to catch bugs early, avoid crashes, and build production-ready applications that gracefully recover from unexpected issues.

🎯 In this guide, you’ll learn:

• PHP error types and what they mean
• How to enable or disable error reporting
• How to log errors instead of displaying them
• Best practices for development vs production environments

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⚠️ PHP Error Types

PHP categorizes errors into the following types:

Constant	Description
E_ERROR	Fatal errors; execution stops
E_WARNING	Runtime warnings; script continues
E_PARSE	Compile-time parse errors
E_NOTICE	Minor notices; undefined variables, etc.
E_DEPRECATED	Usage of deprecated features
E_ALL	Enables all of the above

📌 Use E_ALL during development for complete visibility.

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🔧 Displaying Errors in Development

error_reporting(E_ALL);
ini_set("display_errors", 1);

✅ Shows all warnings, notices, and fatal errors in the browser
📌 Use only in development environments

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🚫 Hiding Errors in Production

ini_set("display_errors", 0);
ini_set("log_errors", 1);
ini_set("error_log", "/var/log/php-errors.log");

✅ Prevents error details from leaking to end users
📌 Always log errors in production for later review

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📋 Error Reporting Control

error_reporting(0); // Suppresses all errors
error_reporting(E_ALL & ~E_NOTICE); // Suppresses notices

📌 You can customize the level of visibility depending on your needs

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📤 Logging Errors to a File

ini_set("log_errors", 1);
ini_set("error_log", "errors.log");

error_log("Something went wrong!");

✅ Useful for debugging production issues
📌 You can send logs to syslog or custom handlers too

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🧪 Triggering Custom Errors

trigger_error("This is a custom warning", E_USER_WARNING);
trigger_error("This is a custom notice", E_USER_NOTICE);

✅ Useful for custom validation logic or soft fail scenarios

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🛠️ Handling Fatal Errors (Shutdown Function)

register_shutdown_function(function () {
    $error = error_get_last();
    if ($error && $error['type'] === E_ERROR) {
        echo "❗ Fatal error occurred: " . $error['message'];
    }
});

📌 Used to catch errors that normally kill the script

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📌 Summary – Recap & Next Steps

PHP error handling gives you control over what happens when your code encounters problems. By properly configuring error reporting and separating development from production behaviors, you build more secure and maintainable applications.

🔍 Key Takeaways:

• Use error_reporting(E_ALL) during development
• Turn off display_errors and enable logging in production
• Understand and classify errors using constants like E_WARNING, E_NOTICE, etc.
• Use trigger_error() for custom error messages
• Register shutdown functions to handle fatal errors

⚙️ Real-World Use Cases:
Form validation, API error responses, runtime diagnostics, crash reporting systems, application uptime alerts

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❓ Frequently Asked Questions (FAQs)

❓ How do I turn on full error reporting?
✅ Use error_reporting(E_ALL); ini_set("display_errors", 1);

❓ Should I use display_errors in production?
❌ No. Use logging (log_errors = 1) instead to keep users safe.

❓ What’s the difference between E_WARNING and E_ERROR?
✅ E_WARNING allows the script to continue. E_ERROR halts execution.

❓ Can I handle E_ERROR using try…catch?
❌ Not directly. Use set_error_handler() or register_shutdown_function() for fatal errors.

❓ Where are PHP error logs stored?
✅ By default, they go to the web server log. You can set error_log manually in php.ini.

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