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<?php //test 1 is defined, but has a value of null. isset will return false, use causes no error. $test1 = null; var_dump($test1); var_dump(isset($test1)); echo "\n----------\n\n"; //test2 is defined with a string value. isset will return true $test2 = "test"; var_dump($test2); var_dump(isset($test2)); echo "\n----------\n\n"; //test3 is not defined, isset returns false and use causes error. var_dump($test3); var_dump(isset($test3));
Finding entry points
Branch analysis from position: 0
1 jumps found. (Code = 62) Position 1 = -2
filename:       /in/Nmk0t
function name:  (null)
number of ops:  26
compiled vars:  !0 = $test1, !1 = $test2, !2 = $test3
line      #* E I O op                           fetch          ext  return  operands
-------------------------------------------------------------------------------------
    3     0  E >   ASSIGN                                                   !0, null
    4     1        INIT_FCALL                                               'var_dump'
          2        SEND_VAR                                                 !0
          3        DO_ICALL                                                 
    5     4        INIT_FCALL                                               'var_dump'
          5        ISSET_ISEMPTY_CV                                 ~5      !0
          6        SEND_VAL                                                 ~5
          7        DO_ICALL                                                 
    7     8        ECHO                                                     '%0A----------%0A%0A'
   10     9        ASSIGN                                                   !1, 'test'
   11    10        INIT_FCALL                                               'var_dump'
         11        SEND_VAR                                                 !1
         12        DO_ICALL                                                 
   12    13        INIT_FCALL                                               'var_dump'
         14        ISSET_ISEMPTY_CV                                 ~9      !1
         15        SEND_VAL                                                 ~9
         16        DO_ICALL                                                 
   14    17        ECHO                                                     '%0A----------%0A%0A'
   17    18        INIT_FCALL                                               'var_dump'
         19        SEND_VAR                                                 !2
         20        DO_ICALL                                                 
   18    21        INIT_FCALL                                               'var_dump'
         22        ISSET_ISEMPTY_CV                                 ~12     !2
         23        SEND_VAL                                                 ~12
         24        DO_ICALL                                                 
         25      > RETURN                                                   1

Generated using Vulcan Logic Dumper, using php 8.0.0


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