PHP Functions Essential Reference

class_exists

bool class_exists(string class_name) 

Tests whether a class is defined.

Returns:

TRUE if the class exists; FALSE for all other cases

Description:

class_exists() is used to check whether the class class_name has been defined. If the class has been defined, the function returns TRUE; otherwise, it returns FALSE.

Availability:

UNIX, Windows

Version:

4.0b4+

See also:

To find the type of a variable:

gettype() 

To find out whether a variable is an object:

is_object() 

Example:

Check to see whether a class is defined

// Why no class can be a nihilist class nihilist { function nihilist () { print ""; // Ha ha - sorry for the crummy nihilist humor... } } if (class_exists ('nihilist')) print "Class <i>nihilist</i> exists.";