Zval

ZVAL is a C structure, that represents data in PHP. It is a structure, which is never directly used from PHP code.

It may be access with debug_zval_dump() function, for debugging purposes. It is useful to debug PHP engine, or extensions.

<?php

    // From the manual
    $var1 = 'Hello';
    $var1 .= ' World';
    $var2 = $var1;

    debug_zval_dump($var1);

    // displays string(11) "Hello World" refcount(3)

?>

Documentation

See also debug_zval_dump.

Related : Zend Engine, Garbage Collection, Reference Count