Predefined Variables, Exceptions, Interfaces, and Classes

Question 1

What are the superglobals?

Answer 1

$GLOBALS
$_SERVER
$_GET
$_POST
$_FILES
$_COOKIE
$_SESSION
$_REQUEST
$_ENV

Question 2

What is $php_errormsg?

Answer 2

It contains the text of the last error message generated by PHP. This variable will only be available within the scope in which the error occurred, and only if the track_errors configuration option is turned on (it defaults to off).

Question 3

What is $http_response_header?

Answer 3

The $http_response_header array is similar to the get_headers() function. When using the HTTP wrapper, $http_response_header will be populated with the HTTP response headers. $http_response_header will be created in the local scope.

Question 4

What is $argc?

Answer 4

It contains the number of arguments passed to the current script when running from the command line.

Question 5

What is $argv?

Answer 5

It contains an array of all the arguments passed to the script when running from the command line.

Question 6

What is Exception?

Answer 6

Exception is the base class for all exceptions.

Question 7

Are Exceptions clonable?

Answer 7

No.

Question 8

What is ErrorException?

Answer 8

A predefined error exception class that extends Exception.

Question 9

What are the predefined interfaces and classes?

Answer 9

Traversable
Iterator
IteratorAggregate
ArrayAccess
Serializable
Closure
Generator

Question 10

How can Traversable be implemented?

Answer 10

It’s an abstract base class that cannot be implemented alone. It must be implemented by either IteratorAggregate or Iterator. It has no methods.

Question 11

Can generator objects be instantiated with new?

Answer 11

No.