What is the meaning of \"::\"?

[Anon]

I would like to ask an question:
What is the meaning of \"::\"? for example, ao_instant::chk_security($fs_close)
Does \"::\" equal to \"->\"
Thx!

[Anon]

i assume that you are working with classes and will answer that way. :: is the scope modifier. if you are working in a class and want a function outside that class you use the scope modifier. like so:

class one
{
function some_function($var)
{
stuff
}
}

class two
{
function other_function($var)
{
stuff
$p = one::some_function($var);
}
}

there is also overriding in classes like so:

class one
{
function my_function()
{
echo "hello world";
}
}

class two extends class one
{
function my_function()
{
one::my_function();
}
}

in class two it makes the call to the function in class one. if you were to use $this->my_function(); in class two, you would be calling the function you were in.

hope that helps.

[Anon]

Thanks for your help but I still don't understand what exactly you mean.

[Anon]

okay, lets see here. i'll give this another shot:

class one
{
function my_function()
{
echo "hello world";
}
}

class two
{
function some_function()
{
one::my_function();
}
}

so we have two classes that have nothing to do with each other. as you see in class two, we are making a call to a function that is in class one. since the function in class one is not in the scope of class two, we use the scope modifier :: to call the function. now if we add inheritance to class two, the scope modifier is not needed. it would then look like so:

class one
{
function my_function()
{
echo "hello world";
}
}

class two extends one
{
function some_function()
{
$this->my_function();
}
}

the only time you need to use the scope modifer in a situation where inheritance is involved is when you are overriding a function. take this example:

class one
{
function my_function()
{
echo "hello world";
}
}

class two extends one
{
function my_function();
{
one::my_function()
}
}

in class one we have a function called my_function(). we have a function with the same name in class two. this means that when you call the function my_function() it will call the function in class two because it has overriden the function in class one. this is where we use the scope modifier :: to call the function in class one rather than the function in class two.

here are a couple pages in the manual that deal with object oriented programming:

http://php.net/manual/en/language.oop.php
http://php.net/manual/en/ref.classobj.php

hope that helps.