From: joliver at gmx dot at Operating system: all PHP version: Irrelevant PHP Bug Type: Documentation problem Bug description: suggest $foo = &new Bar(); for PHP4
Description: ------------ Please provide an advice to PHP4 users to use $foo = &new Bar(); instead of $foo = new Bar(); Contrary to the examples in the documentation, in PHP4 instances of objects should be initialisised with $foo = &new Bar(); because here $foo is a reference to the created instance of Bar, while for $foo = new Bar(); $foo is a copy(!) of the instance. Appart from performance and memory issues, in the second case parameters in the constructors will be copied to, because the whole object is copied. That means for example, that for: $foo = new Bar($this) $foo is an instance of Bar where $this is not the owner of that instance any more, because $foo is a copy of the newly created instance. Good example in german: http://www.usegroup.de/software/phptutorial/klassen_und_objekte.html#ref_owner Reproduce code: --------------- <?php class myC1 { var $greeting; var $theC2; function sayHello() { echo $this->greeting; } function myC1() { $this->greeting="Howdy"; $this->theC2=new myC2($this); } } class myC2 { var $owner; function myC2(&$owner) { $this->owner=&$owner; $this->owner->greeting="bah"; } function something() { $this->owner->greeting="hulla"; // This is supposed to change myC1's greeting to hulla, overwriting "bah". } } $test=new myC1(); //$test=&new myC1(); $test->theC2->something(); $test->sayHello(); ?> Expected result: ---------------- $test=&new myC1(); returns the excepted result in PHP4. Please provide that advice for PHP4 users in the documentation. Actual result: -------------- As described above, $test=new myC1(); returns a copy of the instance, therefore $this in myC1 gets lost. An advice for PHP4 users would be helpful, in my opinion in PHP4 $foo=&new Bar(); should be used instead of $foo=new Bar(;), which is not mentioned anywhere in the documentation. (of course i know in PHP5 this as been fixed because objects are passed by reference.) Thank you! Oliver -- Edit bug report at http://bugs.php.net/?id=38011&edit=1 -- Try a CVS snapshot (PHP 4.4): http://bugs.php.net/fix.php?id=38011&r=trysnapshot44 Try a CVS snapshot (PHP 5.2): http://bugs.php.net/fix.php?id=38011&r=trysnapshot52 Try a CVS snapshot (PHP 6.0): http://bugs.php.net/fix.php?id=38011&r=trysnapshot60 Fixed in CVS: http://bugs.php.net/fix.php?id=38011&r=fixedcvs Fixed in release: http://bugs.php.net/fix.php?id=38011&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=38011&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=38011&r=needscript Try newer version: http://bugs.php.net/fix.php?id=38011&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=38011&r=support Expected behavior: http://bugs.php.net/fix.php?id=38011&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=38011&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=38011&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=38011&r=globals PHP 3 support discontinued: http://bugs.php.net/fix.php?id=38011&r=php3 Daylight Savings: http://bugs.php.net/fix.php?id=38011&r=dst IIS Stability: http://bugs.php.net/fix.php?id=38011&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=38011&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=38011&r=float No Zend Extensions: http://bugs.php.net/fix.php?id=38011&r=nozend MySQL Configuration Error: http://bugs.php.net/fix.php?id=38011&r=mysqlcfg
