3v4l.org

run code in 200+ PHP versions simultaneously
<?php var_dump(iconv_substr('',0,10,'utf-8')); var_dump(substr('',0,10)); var_dump(mb_substr('',0,10));
based on S4R1N
Finding entry points
Branch analysis from position: 0
1 jumps found. (Code = 62) Position 1 = -2
filename:       /in/Q52RB
function name:  (null)
number of ops:  26
compiled vars:  none
line     #* E I O op                           fetch          ext  return  operands
-------------------------------------------------------------------------------------
   3     0  E >   INIT_FCALL                                               'var_dump'
         1        INIT_FCALL                                               'iconv_substr'
         2        SEND_VAL                                                 ''
         3        SEND_VAL                                                 0
         4        SEND_VAL                                                 10
         5        SEND_VAL                                                 'utf-8'
         6        DO_ICALL                                         $0      
         7        SEND_VAR                                                 $0
         8        DO_ICALL                                                 
   4     9        INIT_FCALL                                               'var_dump'
        10        INIT_FCALL                                               'substr'
        11        SEND_VAL                                                 ''
        12        SEND_VAL                                                 0
        13        SEND_VAL                                                 10
        14        DO_ICALL                                         $2      
        15        SEND_VAR                                                 $2
        16        DO_ICALL                                                 
   5    17        INIT_FCALL                                               'var_dump'
        18        INIT_FCALL                                               'mb_substr'
        19        SEND_VAL                                                 ''
        20        SEND_VAL                                                 0
        21        SEND_VAL                                                 10
        22        DO_ICALL                                         $4      
        23        SEND_VAR                                                 $4
        24        DO_ICALL                                                 
        25      > RETURN                                                   1

Generated using Vulcan Logic Dumper, using php 7.4.0