Web Application Development with PHP 4.0

Duplicating Variable Contents: The Copy Constructor

Sooner or later, you may need to assign the contents of one zval container to another. This is easier said than done, since the zval container doesn't contain only type information, but also references to places in Zend's internal data. For example, depending on their size, arrays and objects may be nested with lots of hash table entries. By assigning one zval to another, you avoid duplicating the hash table entries, using only a reference to them (at most).

To copy this complex kind of data, use the copy constructor. Copy constructors are typically defined in languages that support operator overloading, with the express purpose of copying complex types. If you define an object in such a language, ...