Understanding Ampersand Prefixed PHP Functions: Defining, Using, and Benefits
The ampersand character "&" plays a significant role in PHP function syntax, primarily serving to return a variable reference. Let's delve into what this means and how it can be utilized.
What Ampersands Represent in PHP Function Definitions
When used at the beginning of a function declaration, an ampersand signifies that the function will return a reference to a variable instead of merely its value. This technique allows functions to modify the original variable's contents, effectively eliminating the need to pass the variable as an argument.
Benefits of Returning References
Using return references offers several advantages:
Example of Using Ampersand-Prefixed Functions
Consider the following example from the Facebook library:
public function &users_hasAppPermission($ext_perm, $uid=null) { return $this->call_method('facebook.users.hasAppPermission', array('ext_perm' => $ext_perm, 'uid' => $uid)); }
Here, the "users_hasAppPermission" function returns a reference to the result of the "call_method" function, giving the ability to modify the original variable directly.
Returning References vs. Passing by Reference
Though similar in concept, returning references and passing by reference differ. Passing by reference allows functions to modify the original variable passed as an argument, while returning references provides a way to modify the original variable by encapsulating the variable manipulation logic within the function.
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