本文實例講述了php閉包中使用use聲明變量的作用域。分享給大家供大家參考，具體如下：

?php
function getClosure($i)
{
    $i = $i.'-'.date('H:i:s');
    return function ($param) use ($i) {
        echo "--- param: $param ---\n";
        echo "--- i: $i ---\n";
    };
}
$c = getClosure(123);
$i = 456;
$c('test');
sleep(3);
$c2 = getClosure(123);
$c2('test');
$c('test');
/*
output:
--- param: test ---
--- i: 123-21:36:52 ---
--- param: test ---
--- i: 123-21:36:55 ---
--- param: test ---
--- i: 123-21:36:52 ---
*/

如上，閉包中使用use聲明的變量來自于生成閉包實例時所在作用域內的同名變量，而不是來自于運行閉包時所在作用域內的同名變量。

而閉包的函數參數則是和正常的函數參數一樣來自于運行時所在作用域內的同名變量。

以下為opcode：

Finding entry points
Branch analysis from position: 0
Jump found. Position 1 = -2
filename:       /tmp/testclosure.php
function name:  (null)
number of ops:  20
compiled vars:  !0 = $c, !1 = $i, !2 = $c2
line     #* E I O op                           fetch          ext  return  operands
-------------------------------------------------------------------------------------
   2     0  E >   NOP
  11     1        SEND_VAL                                                 123
         2        DO_FCALL                                      1  $0      'getclosure'
         3        ASSIGN                                                   !0, $0
  12     4        ASSIGN                                                   !1, 456
  13     5        INIT_FCALL_BY_NAME                                       !0
         6        SEND_VAL                                                 'test'
         7        DO_FCALL_BY_NAME                              1
  14     8        SEND_VAL                                                 3
         9        DO_FCALL                                      1          'sleep'
  15    10        SEND_VAL                                                 123
        11        DO_FCALL                                      1  $5      'getclosure'
        12        ASSIGN                                                   !2, $5
  16    13        INIT_FCALL_BY_NAME                                       !2
        14        SEND_VAL                                                 'test'
        15        DO_FCALL_BY_NAME                              1
  17    16        INIT_FCALL_BY_NAME                                       !0
        17        SEND_VAL                                                 'test'
        18        DO_FCALL_BY_NAME                              1
  29    19      > RETURN                                                   1
Function %00%7Bclosure%7D%2Ftmp%2Ftestclosure.php0x7fb0115f505:
Finding entry points
Branch analysis from position: 0
Jump found. Position 1 = -2
filename:       /tmp/testclosure.php
function name:  {closure}
number of ops:  12
compiled vars:  !0 = $param, !1 = $i
line     #* E I O op                           fetch          ext  return  operands
-------------------------------------------------------------------------------------
   5     0  E >   RECV                                             !0
         1        FETCH_R                      static              $0      'i'
         2        ASSIGN                                                   !1, $0
   6     3        ADD_STRING                                       ~2      '---+param%3A+'
         4        ADD_VAR                                          ~2      ~2, !0
         5        ADD_STRING                                       ~2      ~2, '+---%0A'
         6        ECHO                                                     ~2
   7     7        ADD_STRING                                       ~3      '---+i%3A+'
         8        ADD_VAR                                          ~3      ~3, !1
         9        ADD_STRING                                       ~3      ~3, '+---%0A'
        10        ECHO                                                     ~3
   8    11      > RETURN                                                   null
End of function %00%7Bclosure%7D%2Ftmp%2Ftestclosure.php0x7fb0115f505
Function getclosure:
Finding entry points
Branch analysis from position: 0
Jump found. Position 1 = -2
filename:       /tmp/testclosure.php
function name:  getClosure
number of ops:  9
compiled vars:  !0 = $i
line     #* E I O op                           fetch          ext  return  operands
-------------------------------------------------------------------------------------
   2     0  E >   RECV                                             !0
   4     1        CONCAT                                           ~0      !0, '-'
         2        SEND_VAL                                                 'H%3Ai%3As'
         3        DO_FCALL                                      1  $1      'date'
         4        CONCAT                                           ~2      ~0, $1
         5        ASSIGN                                                   !0, ~2
   5     6        DECLARE_LAMBDA_FUNCTION                                  '%00%7Bclosure%7D%2Ftmp%2Ftestclosure.php0x7fb0115f5051'
   8     7      > RETURN                                                   ~4
   9     8*     > RETURN                                                   null
End of function getclosure

如上，閉包函數的op_array（相當于類定義）在編譯期完成，但在運行期生成閉包實例（相當于類實例）時會為不同實例綁定不同的use靜態變量（在DECLARE_LAMBDA_FUNCTION中完成）。

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