Exceptions
PHP Manual

The UnderflowException class

(PHP 5 >= 5.1.0)

Introduction

Exception thrown when performing an invalid operation on an empty container, such as removing an element.

Class synopsis

UnderflowException extends RuntimeException {
/* Inherited methods */
final public string Exception::getMessage ( void )
final public Exception Exception::getPrevious ( void )
final public mixed Exception::getCode ( void )
final public string Exception::getFile ( void )
final public int Exception::getLine ( void )
final public array Exception::getTrace ( void )
final public string Exception::getTraceAsString ( void )
public string Exception::__toString ( void )
final private void Exception::__clone ( void )
}
Exceptions
PHP Manual