When passing an undefined variable to a function by reference, e.g. function test(&$var) { /* ... */ } unset($x); test($x); What is the error message?

How do I extend an interface?

What should you do to prevent error while unserializing serialized object of non-existent class?

When an object is serialized, which method will be called, automatically, providing your object with an opportunity to close any resources or otherwise prepare to be serialized?

Can we use mysqli commands to connect to the database ?

What is the keyword to define a class ?

Which PHP syntax depictions is/are incorrect?

Output of the code? $var = 10; function fn() { $var = 20; return $var; } fn(); echo $var;

Which is an iterator class included in Standard PHP Library (SPL) in PHP5?

Which is not a file related function in PHP?

Which variable declaration within a class is invalid in PHP5?