3v4l.org

run code in 300+ PHP versions simultaneously
<?php function foo($a) { bar($a++); } function bar($a) { echo '$a = '.$a."\n"; debug_print_backtrace(); } foo(1);
Output for 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.25, 8.4.1 - 8.4.12
$a = 1 #0 /in/br8Co(2): bar(1) #1 /in/br8Co(4): foo(2)
Output for 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30
$a = 1 #0 bar(1) called at [/in/br8Co:2] #1 foo(2) called at [/in/br8Co:4]
preferences:
108.81 ms | 408 KiB | 5 Q