Re: [PHP] Argument passed by reference?
On Friday 07 April 2006 5:06 pm, tedd wrote: At 1:52 PM -0500 4/6/06, Chris Boget wrote: The way I understand it, pass by reference in php is determined in the function definition and not the function call. Something like: You used to be able to pass by reference at run time. But I see that is no longer allowed... :| So I guess that makes my question moot. Thanks for your help. thnx, Chris Chris: Please forgive my ignorance, but when did that happen? tedd -- --- - http://sperling.com I'm not sure when this happened. I'm fairly new to php, myself. Maybe someone else could answer that? -- Joe Henry www.celebrityaccess.com [EMAIL PROTECTED] -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Argument passed by reference?
Joe Henry wrote: On Friday 07 April 2006 5:06 pm, tedd wrote: At 1:52 PM -0500 4/6/06, Chris Boget wrote: The way I understand it, pass by reference in php is determined in the function definition and not the function call. Something like: You used to be able to pass by reference at run time. But I see that is no longer allowed... :| So I guess that makes my question moot. Thanks for your help. thnx, Chris Chris: Please forgive my ignorance, but when did that happen? I'm not sure when this happened. I'm fairly new to php, myself. Maybe someone else could answer that? It's not that it's not allowed, it's that it should be done differently. You should make the function accept a reference in the definition, not pass in a reference to the function. The manual page has a good, simple example on what to do. http://www.php.net/manual/en/language.references.pass.php -- Postgresql php tutorials http://www.designmagick.com/ -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Argument passed by reference?
It's not that it's not allowed, it's that it should be done
differently. You should make the function accept a reference in the
definition, not pass in a reference to the function.
The manual page has a good, simple example on what to do.
http://www.php.net/manual/en/language.references.pass.php
Chris:
Interesting. One would think (at least I do) it should be the other way around.
Using the example given at the link above:
?php
function foo($var)
{
$var++;
}
$a=5;
foo($a);
// $a is 6 here
?
We have one function that works one way.
?php
function foo($var)
{
$var++;
}
$a=5;
foo($a);
// $a is 6 here
?
However, doing it this way, the function can serve two purposes. I
can send it a reference or I could send it a value. I know that in
this function a value doesn't do anything, but it could if the
function was different.
Plus, in the first function, I can't send it a reference (i.e., a
reference to a reference?).
What's short reasoning for this being recommended this way? What am I
not seeing?
tedd
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Re: [PHP] Argument passed by reference?
tedd wrote:
It's not that it's not allowed, it's that it should be done
differently. You should make the function accept a reference in the
definition, not pass in a reference to the function.
The manual page has a good, simple example on what to do.
http://www.php.net/manual/en/language.references.pass.php
Chris:
Interesting. One would think (at least I do) it should be the other way
around.
Using the example given at the link above:
?php
function foo($var)
{
$var++;
}
$a=5;
foo($a);
// $a is 6 here
?
We have one function that works one way.
?php
function foo($var)
{
$var++;
}
$a=5;
foo($a);
// $a is 6 here
?
However, doing it this way, the function can serve two purposes. I can
send it a reference or I could send it a value. I know that in this
function a value doesn't do anything, but it could if the function was
different.
Plus, in the first function, I can't send it a reference (i.e., a
reference to a reference?).
I'd guess it's to simplify things.
Having been involved in a big cms that used references all over the
place (everything was OO), it was extremely hard to find / track down
where they should be and where they were missing - which caused memory
blow-outs where they were not used, and segfault crashes where they were
incorrectly used.
If they were all in the function definitions, I don't have to worry
about that particular problem.
However, it's something the developers would have to give a definitive
answer on.
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Re: [PHP] Argument passed by reference?
At 1:24 PM -0500 4/6/06, Chris Boget wrote:
Is there a way to test to see if a function argument was passed by
reference instead of by value?
thnx,
Chris
Chris:
As I am sure you know, passing by reference is simply passing the
memory address of the variable to a function instead of it's value.
If the receiving function does something to the variable at that
address, then the value at that address is changed. You can test this
by simply checking the value before and after it's returned from the
function.
For example, the following just passes the memory address of variable
$a to a function. After which, the function alters the variable at
that memory address, but doe not return a value. But, echoing the
variable after the function call shows that the variable has indeed
been altered.
?php
$a = 10;
echo($a br/);
ref($a);
echo($a);
?
?php
function ref($a)
{
$a--;
}
?
HTH's
tedd
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Re: [PHP] Argument passed by reference?
At 1:52 PM -0500 4/6/06, Chris Boget wrote: The way I understand it, pass by reference in php is determined in the function definition and not the function call. Something like: You used to be able to pass by reference at run time. But I see that is no longer allowed... :| So I guess that makes my question moot. Thanks for your help. thnx, Chris Chris: Please forgive my ignorance, but when did that happen? tedd -- http://sperling.com -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Argument passed by reference?
On Thursday 06 April 2006 12:24 pm, Chris Boget wrote:
Is there a way to test to see if a function argument was passed by
reference instead of by value?
thnx,
Chris
The way I understand it, pass by reference in php is determined in the
function definition and not the function call. Something like:
function foo ($bar) {
...
}
Here's a link to that section of the php manual:
http://us3.php.net/manual/en/language.references.pass.php
Hope that helps.
--
Joe Henry
www.celebrityaccess.com
[EMAIL PROTECTED]
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Re: [PHP] Argument passed by reference?
The way I understand it, pass by reference in php is determined in the function definition and not the function call. Something like: You used to be able to pass by reference at run time. But I see that is no longer allowed... :| So I guess that makes my question moot. Thanks for your help. thnx, Chris -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
