PHP return Reference (method name plus &) and local static variable (static)

Read the manual first
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To return a reference from a function, you must use the reference operator & when the function declares and assigns a return value to a variable :

Example 17-13. A reference is returned by the function

<?php function &returns_reference () {$someref = 0;  return $someref;  } $newref = &returns_reference ();//equivalent to $newref = & $someref; ?>

For more information about references, see the explanations of the references.

Looking at a lot of open source code like to use the single-case registration mode

CLASS&NBSP;A{}&NBSP;&NBSP;CLASS&NBSP;B{}&NBSP;&NBSP;FUNCTION&NBSP;&AMP;&NBSP;AA ($name)   {       static  $class  = array ();  //local static variable   does not disappear with the execution of the method   But to stick to the end of the entire source program to end the life cycle       if (! $class [$name])         //so   The declaration/initialization statement here   only works on first declaration       {                          //After you call this method,  static variables are no longer reinitialized value           $class [$ name] = new  $name ();      }       return  $class [$name];  }   $a  = & aa (' a ');   $b  = &NBSP;&AMP;&NBSP;AA (' B ');     $a 2 = & aa (' a ');   $b 2 = &NBSP;&AMP;&NBSP;AA (' B ');     echo  $a  ===  $a 2 ?  ' $a and $a2 are the same instantiated objects <br/> '  :  ';   echo  $b  ===  $b 2 ?  ' $b and $B2 are the same instantiated objects '  :  ';

PHP return Reference (method name plus &) and local static variable (static)