Bug #63714 [Nab]: incorrect global statement

[axdr at bk dot ru]

Edit report at https://bugs.php.net/bug.php?id=63714&edit=1

 ID:                 63714
 User updated by:    axdr at bk dot ru
 Reported by:        axdr at bk dot ru
 Summary:            incorrect global statement
 Status:             Not a bug
 Type:               Bug
 Package:            Scripting Engine problem
 Operating System:   Windows
 PHP Version:        5.4.9
 Block user comment: N
 Private report:     N

 New Comment:

Please, ignore previous comment

function func1() {
  global $gvar;
  $var = &$GLOBALS['var'];
  $GLOBALS['var'] = &$gvar;
  var_dump($var, $GLOBALS['var'], $gvar);
}
function func2() {
  global $gvar;
  global $var;
  $GLOBALS['var'] = &$gvar;
  var_dump($var, $GLOBALS['var'], $gvar);
}

$gvar = 'aaa';
$var = 'bbb';
func1();
echo '<hr>';
$gvar = 'aaa';
$var = 'bbb';
func2();

output: 

string 'bbb'
string 'aaa'
string 'aaa'
--------------------------------------------------------------------------------
string 'bbb'
string 'bbb'
string 'bbb'


Previous Comments:
------------------------------------------------------------------------
[2012-12-08 00:00:31] axdr at bk dot ru

global $var is reference to $GLOBALS['var']
but is not equivalent to $var = &$GLOBALS['var']

$gvar = 'aaa';
$var = 'bbb';
function func2() {
  global $gvar;
  global $var;
  $GLOBALS['var'] = &$gvar;
  var_dump($var, $GLOBALS['var']);
}
function func1() {
  global $gvar;
  $var = &$GLOBALS['var'];
  $GLOBALS['var'] = &$gvar;
  var_dump($var, $GLOBALS['var']);
}
function func3() {
  $gvar = 'aaa';
  $var1 = 'bbb';  // вместо global $var
  $var = &$var1;
  $var1 = &$gvar;
  var_dump($var, $var1);
}
func1();
echo '<hr>';
func2();
echo '<hr>';
func3();

output:
'bbb'
'aaa'
---------
'aaa'
'aaa'
---------
'bbb'
'aaa'

------------------------------------------------------------------------
[2012-12-07 04:08:02] axdr at bk dot ru

Sorry. You are right.
But I think this is irrational. 
It's impossible to read all documentation and to remember word for word.
This is a kind of underwater mine.

------------------------------------------------------------------------
[2012-12-07 02:54:35] larue...@php.net

also see:

<?php
function func() {
    global $a, $b;
    $a = 'aaa'; 
    $b = &$a;
    $b = 'bbb';
}   
    
func();
var_dump($a);

output:
bbb

------------------------------------------------------------------------
[2012-12-07 02:52:22] larue...@php.net

Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to report
a bug at http://bugs.php.net/how-to-report.php

global $a;
  make a local variable 'a' reference to $GLOBALS['a'];

also thinking of:

$b = &$a;  // b reference to a
$b = &$c;  // change reference to c


then:
  global $a, $b;   //b reference to $GLOBALS['b']
  $a = 'aaa';
  $b = &$a;        //b now reference to local $a with GLOBALS['b'] unchanged

------------------------------------------------------------------------
[2012-12-07 02:44:58] axdr at bk dot ru

'global'-declaration kills referencies

  function func() {
    global $a, $b;
    $a = 'aaa';
    $b = &$a;
    echo "$a, $b", '<br>';
    global $a, $b;
    echo "$a, $b";
  }
  func();

output: 
  aaa, aaa
  aaa,

------------------------------------------------------------------------


The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at

    https://bugs.php.net/bug.php?id=63714


-- 
Edit this bug report at https://bugs.php.net/bug.php?id=63714&edit=1