3v4l.org

run code in 200+ PHP versions simultaneously
<?php var_dump(substr_count("aaa", "a", 0, 0));
Output for 7.1.3 - 7.2.6
int(0)
Output for 7.1.0 - 7.1.2
int(3)
Output for 5.6.0 - 7.0.20
Warning: substr_count(): Length should be greater than 0 in /in/fdbpO on line 3 bool(false)