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<?php $a = NULL; $c = ''; print $a ?? '1b'; print "\n"; print $a ?: '2b'; print "\n"; print $c ?? '1d'; print "\n"; print $c ?: '2d'; print "\n"; print $e ?? '1f'; print "\n"; print $e ?: '2f';
Output for 8.0.0 - 8.0.19, 8.1.0 - 8.1.6
1b 2b 2d 1f Warning: Undefined variable $e in /in/ZBAa1 on line 21 2f
Output for 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.34, 7.3.0 - 7.3.31, 7.4.0 - 7.4.29
1b 2b 2d 1f Notice: Undefined variable: e in /in/ZBAa1 on line 21 2f
Output for 7.3.32 - 7.3.33
1b 2b 2d 1f 2f
Output for 4.4.2 - 4.4.9, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.40
Parse error: syntax error, unexpected '?' in /in/ZBAa1 on line 6
Process exited with code 255.
Output for 4.3.0 - 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 '?' in /in/ZBAa1 on line 6
Process exited with code 255.
Output for 4.3.2 - 4.3.4
Parse error: parse error in /in/ZBAa1 on line 6
Process exited with code 255.

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