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Bugs & Features
<?php session_start(); $bar = &$_SESSION['foo']; var_dump($_SESSION['foo']); $foo = 1; ?>
Output for 5.4.0 - 7.2.0
NULL
Output for 5.2.10 - 5.3.29
NULL Warning: Unknown: Your script possibly relies on a session side-effect which existed until PHP 4.2.3. Please be advised that the session extension does not consider global variables as a source of data, unless register_globals is enabled. You can disable this functionality and this warning by setting session.bug_compat_42 or session.bug_compat_warn to off, respectively in Unknown on line 0
Output for 5.2.3 - 5.2.9
NULL Warning: Unknown: Your script possibly relies on a session side-effect which existed until PHP 4.2.3. Please be advised that the session extension does not consider global variables as a source of data, unless register_globals is enabled. You can disable this functionality and this warning by setting session.bug_compat_42 or session.bug_compat_warn to off, respectively. in Unknown on line 0
Output for 5.0.0 - 5.2.2
Warning: session_start(): Cannot send session cookie - headers already sent in /in/llXu7 on line 2 Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at /in/llXu7:2) in /in/llXu7 on line 2 NULL Warning: Unknown: Your script possibly relies on a session side-effect which existed until PHP 4.2.3. Please be advised that the session extension does not consider global variables as a source of data, unless register_globals is enabled. You can disable this functionality and this warning by setting session.bug_compat_42 or session.bug_compat_warn to off, respectively. in Unknown on line 0
Output for 4.3.2 - 4.4.9
Warning: session_start(): Cannot send session cookie - headers already sent in /in/llXu7 on line 2 Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at /in/llXu7:2) in /in/llXu7 on line 2 NULL Warning: Unknown(): Your script possibly relies on a session side-effect which existed until PHP 4.2.3. Please be advised that the session extension does not consider global variables as a source of data, unless register_globals is enabled. You can disable this functionality and this warning by setting session.bug_compat_42 or session.bug_compat_warn to off, respectively. in Unknown on line 0
Output for 4.3.0 - 4.3.1
Warning: session_start() [http://www.php.net/function.session-start]: Cannot send session cookie - headers already sent in /in/llXu7 on line 2 Warning: session_start() [http://www.php.net/function.session-start]: Cannot send session cache limiter - headers already sent (output started at /in/llXu7:2) in /in/llXu7 on line 2 NULL Warning: Unknown(): Your script possibly relies on a session side-effect which existed until PHP 4.2.3. Please be advised that the session extension does not consider global variables as a source of data, unless register_globals is enabled. You can disable this functionality and this warning by setting session.bug_compat_42 or session.bug_compat_warn to off, respectively. in Unknown on line 0