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Open Source Technologies

Notes you to change it from the calling scope. To return a variable by-reference, you need to define
the function as such by placing an and sign in front of the function’s name and in the caller’s
code, assigning the return value by reference to $value:
Example: function and get_global_variable($name)

{
return $GLOBALS[$name];
}
$num = 10;
$value =& get_global_variable(“num”);
print $value . “\n”;

$value = 20;
print $num;
The previous code prints as
10

20
You can see that $num was successfully modified by modifying $value, because it is a reference
to the global variable $num.

You won’t need to use this returning method often. When you do, use it with care, because
forgetting to assign by reference the by-reference returned value can lead to bugs that are
difficult to track down.

7.5 Declaring Function Parameters

As previously mentioned, you can pass an arbitrary amount of arguments to a function. There
are two different ways of passing these arguments. The first is the most common, which is called
passing by value, and the second is called passing by reference. Which kind of argument passing
you would like is specified in the function definition itself and not during the function call.
7.5.1 By-Value Parameters

Here, the argument can be any valid expression, the expression is evaluated, and its value is
assigned to the corresponding variable in the function. For example, here, $x is assigned the
value 8 and $y is assigned the value of $c:
Example: Function pow($x, $y)

{
...
}

pow(2*4, $c);
7.5.2 By-Reference Parameters

Passing by-reference requires the argument to be a variable. Instead of the variable’s value
being passed, the corresponding variable in the function directly refers to the passed variable

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