Syntax:

string SplObjectStorage::serialize()

Parameters:this the function does not take any parameters.Return value:this function returns a string that is a storage representation.The following programs illustrate the SplObjectStorage function::serialize()in PHP:Program 1:  
// Create a new storage class $str = new SplObjectStorage; $obj = new StdClass; $str -> attach ( $obj , " GeeksforGeeks " );  
// Print serialization result echo $str -> serialize(); ?> Exit:

x: i : 1; O: 8: "stdClass": 0: {}, s: 13: "GeeksforGeeks" ;; m: a: ​​0: {}

Program 2: < td class = "code"> $obj1 = new StdClass; $obj2 = new StdClass;  
// Create a new storage class $gfg1 = new SplObjectStorage(); $gfg1 [ $obj1 ] = "Geeks" ;  
// Create a new storage class $gfg2 = new SplObjectStorage(); $gfg2 [ $obj1 ] = "GFG" ; $gfg2 [ $obj2 ] = "GeeksClasses" ; print_r ( $gfg1 -> serialize(). " " ); echo ( $gfg2 -> serialize(). "" );  
?> Exit:

x: i : 1; O: 8: "stdClass": 0: {}, s: 5: "Geeks" ;; m: a: ​​0: {} x: i: 2; O: 8: "stdClass": 0: { }, s: 3: "GFG" ;; O: 8: "stdClass": 0: {}, s: 12: "GeeksClasses" ;; m: a: ​​0: {}

Link: https://www.php.net/manual/en/splobjectstorage.serialize.php