3v4l.org

run code in 500+ PHP versions simultaneously
<?php var_dump(mb_substr('Hello I am a string', 6, NULL, 'UTF-8')); var_dump(mb_substr('Hello I am a string', 6, NULL)); var_dump(mb_substr('Hello I am a string', 6));
Finding entry points
Branch analysis from position: 0
1 jumps found. (Code = 62) Position 1 = -2
filename:       /in/iEirS
function name:  (null)
number of ops:  25
compiled vars:  none
line      #* E I O op                               fetch          ext  return  operands
-----------------------------------------------------------------------------------------
    4     0  E >   INIT_FCALL                                                   'var_dump'
          1        INIT_FCALL                                                   'mb_substr'
          2        SEND_VAL                                                     'Hello+I+am+a+string'
          3        SEND_VAL                                                     6
          4        SEND_VAL                                                     null
          5        SEND_VAL                                                     'UTF-8'
          6        DO_ICALL                                             $0      
          7        SEND_VAR                                                     $0
          8        DO_ICALL                                                     
    5     9        INIT_FCALL                                                   'var_dump'
         10        INIT_FCALL                                                   'mb_substr'
         11        SEND_VAL                                                     'Hello+I+am+a+string'
         12        SEND_VAL                                                     6
         13        SEND_VAL                                                     null
         14        DO_ICALL                                             $2      
         15        SEND_VAR                                                     $2
         16        DO_ICALL                                                     
    7    17        INIT_FCALL                                                   'var_dump'
         18        INIT_FCALL                                                   'mb_substr'
         19        SEND_VAL                                                     'Hello+I+am+a+string'
         20        SEND_VAL                                                     6
         21        DO_ICALL                                             $4      
         22        SEND_VAR                                                     $4
         23        DO_ICALL                                                     
         24      > RETURN                                                       1

Generated using Vulcan Logic Dumper, using php 8.5.0


preferences:
162.57 ms | 2152 KiB | 10 Q