3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = 'abc'; echo "Not passing encoding: "; echo mb_substr($a, 0); echo "\n"; echo "Passing null, and encoding: "; echo mb_substr($a, 0, null, 'utf-8'); echo "\n";
Finding entry points
Branch analysis from position: 0
1 jumps found. (Code = 62) Position 1 = -2
filename:       /in/LItvQ
function name:  (null)
number of ops:  18
compiled vars:  !0 = $a
line      #* E I O op                           fetch          ext  return  operands
-------------------------------------------------------------------------------------
    2     0  E >   ASSIGN                                                   !0, 'abc'
    4     1        ECHO                                                     'Not+passing+encoding%3A+'
    5     2        INIT_FCALL                                               'mb_substr'
          3        SEND_VAR                                                 !0
          4        SEND_VAL                                                 0
          5        DO_ICALL                                         $2      
          6        ECHO                                                     $2
    6     7        ECHO                                                     '%0A'
    8     8        ECHO                                                     'Passing+null%2C+and+encoding%3A+'
    9     9        INIT_FCALL                                               'mb_substr'
         10        SEND_VAR                                                 !0
         11        SEND_VAL                                                 0
         12        SEND_VAL                                                 null
         13        SEND_VAL                                                 'utf-8'
         14        DO_ICALL                                         $3      
         15        ECHO                                                     $3
   10    16        ECHO                                                     '%0A'
         17      > RETURN                                                   1

Generated using Vulcan Logic Dumper, using php 8.0.0


preferences:
163.97 ms | 1394 KiB | 15 Q