Error Handling in PHP

Question 1

Q: What is error handling in PHP?

Answer 1

A: The process of catching and managing errors to prevent application crashes.

Question 2

Q: What are the types of errors in PHP?

Answer 2

A: Notices, Warnings, Fatal Errors, and Parse Errors.

Question 3

Q: What function is used to trigger a user-defined error in PHP?

Answer 3

A: trigger_error().

Question 4

Q: What is the default error reporting level in PHP?

Answer 4

A: E_ALL.

Question 5

Q: How do you enable error reporting in PHP?

Answer 5

ini_set(‘display_errors’, 1);
error_reporting(E_ALL);

Question 6

Q: What does E_NOTICE represent in PHP?

Answer 6

A: Non-critical runtime errors, like using undefined variables.

Question 7

Q: What does E_WARNING represent in PHP?

Answer 7

A: Runtime errors that do not halt script execution.

Question 8

Q: What does E_ERROR represent in PHP?

Answer 8

A: Critical runtime errors that halt script execution.

Question 9

Q: What does E_PARSE represent in PHP?

Answer 9

A: Errors that occur during code parsing, such as syntax errors.

Question 10

Q: What does E_ALL represent in PHP?

Answer 10

A: Reports all PHP errors except E_STRICT prior to PHP 5.4.

Question 11

Q: What function retrieves the last error that occurred in PHP?

Answer 11

A: error_get_last().

Question 12

Q: What function logs errors to a file in PHP?

Answer 12

A: error_log().

Question 13

Q: How do you set a custom error handler in PHP?

Answer 13

A: Use the set_error_handler() function.

Question 14

Q: How do you restore the previous error handler in PHP?

Answer 14

A: Use the restore_error_handler() function.

Question 15

Q: How do you set a shutdown function to handle fatal errors?

Answer 15

A: Use the register_shutdown_function() function.

Question 16

Q: What is the syntax for a custom error handler in PHP?

Answer 16

function customError($errno, $errstr, $errfile, $errline) {
// Handle the error
}
set_error_handler(‘customError’);

Question 17

Q: What are the parameters of a custom error handler?

Answer 17

A: Error number, error message, error file, and error line.

Question 18

Q: Can you suppress errors in PHP?

Answer 18

A: Yes, using the @ error control operator.

Question 19

Q: Why should you avoid using the @ operator?

Answer 19

A: It hides all errors, making debugging difficult.

Question 20

Q: What does set_error_handler() return?

Answer 20

A: The previous error handler if successful, or NULL on failure.

Question 21

Q: What is an exception in PHP?

Answer 21

A: A way to handle errors and special conditions using try-catch blocks.

Question 22

Q: What keyword is used to throw an exception?

Answer 22

A: throw.

Question 23

Q: How do you define a try-catch block in PHP?

Answer 23

try {
// Code that may throw an exception
} catch (Exception $e) {
// Handle the exception
}

Question 24

Q: What method retrieves the message from an exception object?

Answer 24

A: $e->getMessage().

Question 25

Q: What is the purpose of the finally block in PHP?

Answer 25

A: To execute code regardless of whether an exception was thrown or not.

Question 26

Q: How do you create a custom exception class in PHP?

Answer 26

A: Extend the Exception class:

class MyException extends Exception {
// Custom methods or properties
}

Question 27

Q: Can you catch multiple exceptions in a single try block?

Answer 27

A: Yes, by using multiple catch blocks.

Question 28

Q: What is the getCode() method of an exception?

Answer 28

A: Retrieves the exception’s error code.

Question 29

Q: What is the getFile() method of an exception?

Answer 29

A: Retrieves the file where the exception was thrown.

Question 30

Q: What is the getLine() method of an exception?

Answer 30

A: Retrieves the line number where the exception was thrown.

Question 31

Q: How do you enable error logging in PHP?

Answer 31

ini_set(‘log_errors’, 1);
ini_set(‘error_log’, ‘/path/to/logfile.log’);

Question 32

Q: What does error_log() do in PHP?

Answer 32

A: Sends an error message to the defined log file, email, or system log.

Question 33

Q: How can you set a custom error log file in php.ini?

Answer 33

A: error_log = /path/to/logfile.log.

Question 34

Q: What is the default location for PHP error logs?

Answer 34

A: It varies by server configuration but is typically in the web server’s error log.

Question 35

Q: How can you log errors to an email in PHP?

Answer 35

A: Use the error_log() function with the 3 parameter and a mail handler.

Question 36

Q: Why should you not display errors in a production environment?

Answer 36

A: It exposes sensitive information to users.

Question 37

Q: How can you disable error display in PHP?

Answer 37

ini_set(‘display_errors’, 0);

Question 38

Q: Why is it important to use error logging?

Answer 38

A: To track and debug issues without exposing them to end-users.

Question 39

Q: How do you test error handling in development?

Answer 39

A: Enable full error reporting using error_reporting(E_ALL).

Question 40

Q: What is the difference between die() and exceptions for handling errors?

Answer 40

A: die() stops script execution immediately, while exceptions allow controlled error handling.