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run code in 300+ PHP versions simultaneously
<?php echo preg_replace_callback('/a/', function($m) { for($i = 0; $i < 10000; $i++) preg_replace('/foo'.$i.'bar/', 'baz', '???foo'.$i.'bar???'); return 'b'; }, 'aa');
Output for 5.5.27 - 5.5.38, 5.6.11 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.30, 7.4.0 - 7.4.23, 8.0.0 - 8.0.10, 8.1rc1 - rc2
bb
Output for 5.4.41 - 5.4.45, 5.6.0 - 5.6.10
Output for 5.4.0 - 5.4.40, 5.5.0 - 5.5.26
ba
Output for 5.3.0 - 5.3.29

Process exited with code 139.
Output for 4.4.2 - 4.4.9, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17
Parse error: syntax error, unexpected T_FUNCTION in /in/1cRNo on line 3
Process exited with code 255.
Output for 4.3.1, 4.3.5 - 4.3.11, 4.4.0 - 4.4.1, 5.0.0 - 5.0.5
Parse error: parse error, unexpected T_FUNCTION in /in/1cRNo on line 3
Process exited with code 255.
Output for 4.3.2 - 4.3.4
Parse error: parse error in /in/1cRNo on line 3
Process exited with code 255.

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107.43 ms | 465 KiB | 5 Q