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run code in 200+ php & hhvm versions
Bugs & Features
<?php echo preg_match('^[a-z]{2}-[A-Z]{2}$', 'en-US');
Output for 5.6.0 - 5.6.30, 7.0.0 - 7.3.0rc3
Warning: preg_match(): No ending delimiter '^' found in /in/CC7tE on line 3
Output for hhvm-3.15.4
Warning: No ending delimiter '^' found: [^[a-z]{2}-[A-Z]{2}$] in /in/CC7tE on line 3