CI source references use--php to refer to demo, static variables and reference relationships

CI source references are used in common.php to load configuration and class methods

function &test ()
{
static $a = ';
if (! $a) {
$a = 2;
}
return $a;
}

$test =& test ();
Echo $test;
$test = 3;
echo Test ();

The result is 23.

References: Methods and variables that use methods point to the same piece of content: Modify the used variable, and the internal value of the method will also change

Note: Both methods and usage are required &

Static variables and reference relationships

/**
* Get Configuration Items
*/
function Config_item ($item)
{
Static $_config;

if (empty ($_config)) {

A reference cannot be assigned directly to a static variable and can be assigned to a static variable array
$_config[0] =& get_config ();
}

return $_config[0][$item];
}

CI source references use--php to refer to demo, static variables and reference relationships