Using Variable Variables works fine inside functions for global
defined variables if you declare them as global inside the function.
Suprinsingly, it does not seem to work with superglobals. Take the
following example:
// code ////////////////////////////////////////////////////////////
<?php
$glob_var="Var 1";
$var_glob_var="glob_var";
$var_ENV="_ENV";
echo $_ENV["OS"],"\n";
echo $glob_var,"\n\n";
echo $var_glob_var,"\n";
echo $var_ENV,"\n\n";
echo $$var_glob_var,"\n";
echo ${$var_ENV}["OS"],"\n\n";
foo1($var_glob_var);
foo2($var_glob_var);
foo3();
foo4();
foo5($var_ENV);
foo6($var_ENV);
foo7();
foo8();
foo9();
function foo1($arg){
echo "--- In foo1 --------------\n";
echo $arg,"\n";
echo $$arg,"\n";
echo "--------------------------\n";
}
function foo2($arg){
global $glob_var;
echo "--- In foo2 --------------\n";
echo $arg,"\n";
echo $$arg,"\n";
echo "--------------------------\n";
}
function foo3(){
$arg="glob_var";
echo "--- In foo3 --------------\n";
echo $arg,"\n";
echo $$arg,"\n";
echo "--------------------------\n";
}
function foo4(){
global $glob_var;
$arg="glob_var";
echo "--- In foo4 --------------\n";
echo $arg,"\n";
echo $$arg,"\n";
echo "--------------------------\n";
}
function foo5($arg){
echo "--- In foo5 --------------\n";
echo $arg,"\n";
echo ${$arg}["OS"],"\n";
echo "--------------------------\n";
}
function foo6($arg){
global $_ENV;
echo "--- In foo6 --------------\n";
echo $arg,"\n";
echo ${$arg}["OS"],"\n";
echo "--------------------------\n";
}
function foo7(){
$arg="_ENV";
echo "--- In foo7 --------------\n";
echo $arg,"\n";
echo ${$arg}["OS"],"\n";
echo "--------------------------\n";
}
function foo8(){
global $_ENV;
$arg="_ENV";
echo "--- In foo8 --------------\n";
echo $arg,"\n";
echo ${$arg}["OS"],"\n";
echo "--------------------------\n";
}
function foo9(){
echo "--- In foo9 --------------\n";
echo $_ENV["OS"],"\n";
echo "--------------------------\n";
}
?>
// Output /////////////////////////////////////////////////////////
Windows_NT
Var 1
glob_var
_ENV
Var 1
Windows_NT
--- In foo1 --------------
glob_var
--- In foo2 --------------
glob_var
Var 1
--- In foo3 --------------
glob_var
--- In foo4 --------------
glob_var
Var 1
--- In foo5 --------------
_ENV
--- In foo6 --------------
_ENV
--- In foo7 --------------
_ENV
--- In foo8 --------------
_ENV
--- In foo9 --------------
Windows_NT
// Version //////////////////////////////////////////////
PHP 4.3.7 (cgi-fcgi) (built: Jun 2 2004 15:49:31)
Copyright (c) 1997-2004 The PHP Group
Zend Engine v1.3.0, Copyright (c) 1998-2004 Zend Technologies
// End //////////////////////////////////////////////////
I'm doing something wrong? Or this is the expected behavior?
Thank you in advance
Right. Variable variables don't work with super-globals and I think it is
documented in this way.
This is on purpose as we decided to only support them this way both for
clarity reasons and for performance.
There are no plans to change this.
Andi
At 01:35 AM 8/5/2004 +0200, A.Rico wrote:
Using Variable Variables works fine inside functions for global
defined variables if you declare them as global inside the function.
Suprinsingly, it does not seem to work with superglobals. Take the
following example:// code ////////////////////////////////////////////////////////////
<?php
$glob_var="Var 1";$var_glob_var="glob_var";
$var_ENV="_ENV";echo $_ENV["OS"],"\n";
echo $glob_var,"\n\n";echo $var_glob_var,"\n";
echo $var_ENV,"\n\n";echo $$var_glob_var,"\n";
echo ${$var_ENV}["OS"],"\n\n";foo1($var_glob_var);
foo2($var_glob_var);
foo3();
foo4();
foo5($var_ENV);
foo6($var_ENV);
foo7();
foo8();
foo9();function foo1($arg){
echo "--- In foo1 --------------\n";
echo $arg,"\n";
echo $$arg,"\n";
echo "--------------------------\n";
}
function foo2($arg){
global $glob_var;echo "--- In foo2 --------------\n";
echo $arg,"\n";
echo $$arg,"\n";
echo "--------------------------\n";
}
function foo3(){
$arg="glob_var";
echo "--- In foo3 --------------\n";
echo $arg,"\n";
echo $$arg,"\n";
echo "--------------------------\n";
}
function foo4(){
global $glob_var;$arg="glob_var";
echo "--- In foo4 --------------\n";
echo $arg,"\n";
echo $$arg,"\n";
echo "--------------------------\n";
}
function foo5($arg){
echo "--- In foo5 --------------\n";
echo $arg,"\n";
echo ${$arg}["OS"],"\n";
echo "--------------------------\n";
}
function foo6($arg){
global $_ENV;echo "--- In foo6 --------------\n";
echo $arg,"\n";
echo ${$arg}["OS"],"\n";
echo "--------------------------\n";
}
function foo7(){
$arg="_ENV";echo "--- In foo7 --------------\n";
echo $arg,"\n";
echo ${$arg}["OS"],"\n";
echo "--------------------------\n";
}
function foo8(){
global $_ENV;
$arg="_ENV";echo "--- In foo8 --------------\n";
echo $arg,"\n";
echo ${$arg}["OS"],"\n";
echo "--------------------------\n";
}
function foo9(){
echo "--- In foo9 --------------\n";
echo $_ENV["OS"],"\n";
echo "--------------------------\n";
}
?>// Output /////////////////////////////////////////////////////////
Windows_NT
Var 1glob_var
_ENVVar 1
Windows_NT--- In foo1 --------------
glob_var
--- In foo2 --------------
glob_var
Var 1--- In foo3 --------------
glob_var
--- In foo4 --------------
glob_var
Var 1--- In foo5 --------------
_ENV
--- In foo6 --------------
_ENV
--- In foo7 --------------
_ENV
--- In foo8 --------------
_ENV
--- In foo9 --------------
Windows_NT// Version //////////////////////////////////////////////
PHP 4.3.7 (cgi-fcgi) (built: Jun 2 2004 15:49:31)
Copyright (c) 1997-2004 The PHP Group
Zend Engine v1.3.0, Copyright (c) 1998-2004 Zend Technologies// End //////////////////////////////////////////////////
I'm doing something wrong? Or this is the expected behavior?
Thank you in advance
What the PHP documentation says about variable variables and
superglobals is that you can't use them as a "pointer":
/*Warning*/
/ Please note that variable variables cannot be used with PHP's
Superglobal arrays
<http://www.php.net/manual/en/language.variables.predefined.php#language.variables.superglobals>.
This means you cannot do things like ${$_GET}. If you are looking
for a way to handle availability of superglobals and the old
HTTP_*_VARS, you might want to try referencing
<http://www.php.net/manual/en/language.references.php> them. /
what I intended was to use a "normal" globally defined variable to
"point" to a superglobal; that, in fact, works in the global scope, but
not in the function scope:
// Code //////////////////////////////////////////////////////////////
$varvar="_ENV";
echo $_ENV["OS"]; // --> Windows NT
echo ${$varvar}; // --> Windows NT
foo($varvar);
function foo($arg){
$lvar="_ENV";
echo $_ENV["OS"]; // --> Windows NT
echo ${$arg}["OS"]; // --> *nothing*
echo ${$lvar}["OS"]; // --> *nothing*
var_dump( $$arg ); // --> `NULL`
var_dump( $$lvar); // --> `NULL`
}
// END //////////////////////////////////////////////////////////////
Regards,
A. Rico
function foo($arg){
$lvar="_ENV";echo $_ENV["OS"]; // --> Windows NT echo ${$arg}["OS"]; // --> *nothing* echo ${$lvar}["OS"]; // --> *nothing* var_dump( $$arg ); // --> `NULL` var_dump( $$lvar); // --> `NULL`}
// END //////////////////////////////////////////////////////////////
echo $GLOBALS[$lvar]['OS'];
- Thus wrote A.Rico:
What the PHP documentation says about variable variables and
superglobals is that you can't use them as a "pointer":/Warning/
/ Please note that variable variables cannot be used with PHP's
Superglobal arrays
http://www.php.net/manual/en/language.variables.predefined.php#language.variables.superglobals.
This means you cannot do things like ${$GET}. If you are looking
for a way to handle availability of superglobals and the old
HTTP*_VARS, you might want to try referencing
http://www.php.net/manual/en/language.references.php them. /what I intended was to use a "normal" globally defined variable to
"point" to a superglobal; that, in fact, works in the global scope, but
not in the function scope:// Code //////////////////////////////////////////////////////////////
$varvar="_ENV";echo $_ENV["OS"]; // --> Windows NT
echo ${$varvar}; // --> Windows NT
This is a documentation issue, i believe, as noted on:
http://php.net/variables.predefined
Variable variables super globals aren't allowed inside functions or
methods. The waring on the page you reference is fixed in the docs
reflecting this.
Curt
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