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run code in 150+ php & hhvm versions
Bugs & Features
<?php var_dump(preg_match('/b(?<a>a)?/', 'xxxxbxxxx'));
Output for 4.4.6 - 4.4.9, 5.2.2 - 7.1.0
int(1)
Output for 4.3.11 - 4.4.5, 5.0.0 - 5.2.1
Warning: preg_match(): Compilation failed: unrecognized character after (?< at offset 4 in /in/nbK5m on line 3 bool(false)
Output for 4.3.0 - 4.3.10
Warning: Compilation failed: unrecognized character after (?< at offset 4 in /in/nbK5m on line 3 bool(false)