3v4l.org

run code in 300+ PHP versions simultaneously
<?php // Source: https://bugs.php.net/bug.php?id=62922 var_dump(substr("", 0)); var_dump(substr("a", 1)); var_dump(substr("ab", 2));
Finding entry points
Branch analysis from position: 0
1 jumps found. (Code = 62) Position 1 = -2
filename:       /in/HUlq2
function name:  (null)
number of ops:  22
compiled vars:  none
line      #* E I O op                           fetch          ext  return  operands
-------------------------------------------------------------------------------------
    4     0  E >   INIT_FCALL                                               'var_dump'
          1        INIT_FCALL                                               'substr'
          2        SEND_VAL                                                 ''
          3        SEND_VAL                                                 0
          4        DO_ICALL                                         $0      
          5        SEND_VAR                                                 $0
          6        DO_ICALL                                                 
    5     7        INIT_FCALL                                               'var_dump'
          8        INIT_FCALL                                               'substr'
          9        SEND_VAL                                                 'a'
         10        SEND_VAL                                                 1
         11        DO_ICALL                                         $2      
         12        SEND_VAR                                                 $2
         13        DO_ICALL                                                 
    6    14        INIT_FCALL                                               'var_dump'
         15        INIT_FCALL                                               'substr'
         16        SEND_VAL                                                 'ab'
         17        SEND_VAL                                                 2
         18        DO_ICALL                                         $4      
         19        SEND_VAR                                                 $4
         20        DO_ICALL                                                 
         21      > RETURN                                                   1

Generated using Vulcan Logic Dumper, using php 8.0.0


preferences:
180.97 ms | 1395 KiB | 17 Q