Passing parameters by value and by reference to a function in PHP

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Passing parameters by value and by reference to a function in PHP

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Passing parameters to a function in PHP

last updated: 5 December 2024

1) Pass parameters by value to a function

Any parameter that is passed to the function does not change the value when the function exits.
That is, when we pass a parameter to a function, a copy of this parameter is created and inside the function we work with a copy of the parameter.

Example

PHP

<?php

     // declare a function
     function SetValue($x)
     {
          $x = 10;
     }

     // create a variable
     $a = 20;

     // call the function
     SetValue($a);

     print($a); // we will see on the screen 20
?>

2) Pass parameters by reference to the function

To pass a parameter to a function by reference, you need to use &
When you pass a parameter to a function by reference, such a parameter is passed inside the function and we work with this parameter.
When you exit the function, the parameter changes the value

Example

PHP

<?php

     // declare a function
     function SetValue(& $x)
     {
          $x = 10;
     }

     // create a variable
     $a = 20;

     // call the function
     SetValue($a);

     print($a); // we will see on the screen 10
?>

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