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<?php header('X-foo: bar'); session_id('foobar'); var_dump(session_id()); session_write_close(); session_start(); session_id(''); var_dump(session_id()); ?>
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.4, 8.3.6 - 8.3.7
string(6) "foobar" Warning: session_start(): Session cannot be started after headers have already been sent in /in/9GTWE on line 6 Warning: session_id(): Session ID cannot be changed after headers have already been sent in /in/9GTWE on line 7 string(6) "foobar"
Output for 8.3.5
Warning: PHP Startup: Unable to load dynamic library 'sodium.so' (tried: /usr/lib/php/8.3.5/modules/sodium.so (libsodium.so.23: cannot open shared object file: No such file or directory), /usr/lib/php/8.3.5/modules/sodium.so.so (/usr/lib/php/8.3.5/modules/sodium.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0 string(6) "foobar" Warning: session_start(): Session cannot be started after headers have already been sent in /in/9GTWE on line 6 Warning: session_id(): Session ID cannot be changed after headers have already been sent in /in/9GTWE on line 7 string(6) "foobar"
Output for 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33
string(6) "foobar" Warning: session_start(): Cannot start session when headers already sent in /in/9GTWE on line 6 Warning: session_id(): Cannot change session id when headers already sent in /in/9GTWE on line 7 string(6) "foobar"
Output for 7.1.0 - 7.1.33
string(6) "foobar" Warning: session_start(): Cannot send session cookie - headers already sent by (output started at /in/9GTWE:4) in /in/9GTWE on line 6 Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at /in/9GTWE:4) in /in/9GTWE on line 6 string(0) ""
Output for 7.0.0 - 7.0.24
string(6) "foobar" Warning: session_start(): Cannot send session cookie - headers already sent by (output started at /in/9GTWE:4) in /in/9GTWE on line 6 Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at /in/9GTWE:4) in /in/9GTWE on line 6 string(0) "" Warning: Unknown: The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in Unknown on line 0 Warning: Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct () in Unknown on line 0

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