3v4l.org

run code in 500+ PHP versions simultaneously
<?php echo "Normal match:\n"; preg_match('/two/', 'two', $match); var_dump($match); echo "Unmatched $1 is not reported:\n"; preg_match('/(one)?two/', 'two', $match); var_dump($match); preg_match('/two(three)?/', 'two', $match); var_dump($match); echo "Unmatched $1 is reported if $2 is set:\n"; preg_match('/(one)?(two)/', 'two', $match); var_dump($match); echo "Unmatched $2 is not reported even though $1 is set:\n"; preg_match('/(two)(three)?/', 'two', $match); var_dump($match);
Finding entry points
Branch analysis from position: 0
1 jumps found. (Code = 62) Position 1 = -2
filename:       /in/MjB11
function name:  (null)
number of ops:  45
compiled vars:  !0 = $match
line      #* E I O op                               fetch          ext  return  operands
-----------------------------------------------------------------------------------------
    3     0  E >   ECHO                                                         'Normal+match%3A%0A'
    4     1        INIT_FCALL                                                   'preg_match'
          2        SEND_VAL                                                     '%2Ftwo%2F'
          3        SEND_VAL                                                     'two'
          4        SEND_REF                                                     !0
          5        DO_ICALL                                                     
    5     6        INIT_FCALL                                                   'var_dump'
          7        SEND_VAR                                                     !0
          8        DO_ICALL                                                     
    7     9        ECHO                                                         'Unmatched+%241+is+not+reported%3A%0A'
    8    10        INIT_FCALL                                                   'preg_match'
         11        SEND_VAL                                                     '%2F%28one%29%3Ftwo%2F'
         12        SEND_VAL                                                     'two'
         13        SEND_REF                                                     !0
         14        DO_ICALL                                                     
    9    15        INIT_FCALL                                                   'var_dump'
         16        SEND_VAR                                                     !0
         17        DO_ICALL                                                     
   11    18        INIT_FCALL                                                   'preg_match'
         19        SEND_VAL                                                     '%2Ftwo%28three%29%3F%2F'
         20        SEND_VAL                                                     'two'
         21        SEND_REF                                                     !0
         22        DO_ICALL                                                     
   12    23        INIT_FCALL                                                   'var_dump'
         24        SEND_VAR                                                     !0
         25        DO_ICALL                                                     
   14    26        ECHO                                                         'Unmatched+%241+is+reported+if+%242+is+set%3A%0A'
   15    27        INIT_FCALL                                                   'preg_match'
         28        SEND_VAL                                                     '%2F%28one%29%3F%28two%29%2F'
         29        SEND_VAL                                                     'two'
         30        SEND_REF                                                     !0
         31        DO_ICALL                                                     
   16    32        INIT_FCALL                                                   'var_dump'
         33        SEND_VAR                                                     !0
         34        DO_ICALL                                                     
   18    35        ECHO                                                         'Unmatched+%242+is+not+reported+even+though+%241+is+set%3A%0A'
   19    36        INIT_FCALL                                                   'preg_match'
         37        SEND_VAL                                                     '%2F%28two%29%28three%29%3F%2F'
         38        SEND_VAL                                                     'two'
         39        SEND_REF                                                     !0
         40        DO_ICALL                                                     
   20    41        INIT_FCALL                                                   'var_dump'
         42        SEND_VAR                                                     !0
         43        DO_ICALL                                                     
         44      > RETURN                                                       1

Generated using Vulcan Logic Dumper, using php 8.5.0


preferences:
160.34 ms | 2085 KiB | 15 Q