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<?php // inspired by discussion at: http://stackoverflow.com/questions/11158772/assigning-null-to-a-variable-in-php-what-does-that-do $a = 1; $a = null; echo isset($a) ? 'true' : 'false', "\n"; // false var_dump($a); // 'NULL' -- but no error notice - bug ? type changed to NULL unset($a); // now variable undefined echo isset($a) ? 'true' : 'false', "\n"; // false var_dump($a); // error notice and value NULL
Finding entry points
Branch analysis from position: 0
2 jumps found. (Code = 43) Position 1 = 4, Position 2 = 6
Branch analysis from position: 4
1 jumps found. (Code = 42) Position 1 = 7
Branch analysis from position: 7
2 jumps found. (Code = 43) Position 1 = 15, Position 2 = 17
Branch analysis from position: 15
1 jumps found. (Code = 42) Position 1 = 18
Branch analysis from position: 18
1 jumps found. (Code = 62) Position 1 = -2
Branch analysis from position: 17
1 jumps found. (Code = 62) Position 1 = -2
Branch analysis from position: 6
2 jumps found. (Code = 43) Position 1 = 15, Position 2 = 17
Branch analysis from position: 15
Branch analysis from position: 17
filename:       /in/4oZkL
function name:  (null)
number of ops:  24
compiled vars:  !0 = $a
line      #* E I O op                           fetch          ext  return  operands
-------------------------------------------------------------------------------------
    3     0  E >   ASSIGN                                                   !0, 1
    4     1        ASSIGN                                                   !0, null
    5     2        ISSET_ISEMPTY_CV                                         !0
          3      > JMPZ                                                     ~3, ->6
          4    >   QM_ASSIGN                                        ~4      'true'
          5      > JMP                                                      ->7
          6    >   QM_ASSIGN                                        ~4      'false'
          7    >   ECHO                                                     ~4
          8        ECHO                                                     '%0A'
    6     9        INIT_FCALL                                               'var_dump'
         10        SEND_VAR                                                 !0
         11        DO_ICALL                                                 
    7    12        UNSET_CV                                                 !0
    8    13        ISSET_ISEMPTY_CV                                         !0
         14      > JMPZ                                                     ~6, ->17
         15    >   QM_ASSIGN                                        ~7      'true'
         16      > JMP                                                      ->18
         17    >   QM_ASSIGN                                        ~7      'false'
         18    >   ECHO                                                     ~7
         19        ECHO                                                     '%0A'
    9    20        INIT_FCALL                                               'var_dump'
         21        SEND_VAR                                                 !0
         22        DO_ICALL                                                 
         23      > RETURN                                                   1

Generated using Vulcan Logic Dumper, using php 8.0.0


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