What is the difference between closures and anonymous functions in php

Collectives on Stack Overflow. Learn more. Closure vs Anonymous function difference? Asked 10 years, 9 months ago. Active 9 years, 2 months ago. Viewed 26k times. Improve this question. Community Bot 1 1 1 silver badge. Maxim Gershkovich Maxim Gershkovich 43k 42 42 gold badges silver badges bronze badges. Nope but it is a duplicate of stackoverflow. Add a comment. Active Oldest Votes. Improve this answer. Anurag Anurag k 35 35 gold badges silver badges bronze badges.

When you define a regular function you give it a name myRegularFunction in this cases. Now you can refer to this function using function name. For example, you can call this function like this-. Anonymous functions are similar to the regular function as they can contain the same type of code, they accept arguments, return values and all… The key difference is — as the name implies — anonymous functions have no name.

Here is an example of an anonymous function. If you have noticed there are two key difference between a regular function and an anonymous function. This function cannot be referred anywhere but you can do a lot of handy things with it-. While creating an anonymous function, it can also be assigned to a variable just like any other value.

Here is an example-. One common use of the anonymous function is to create a simple inline callback function. A callback function is a function that you can pass to another function as an argument. Once you access your callback function the receiving function can use it whenever it needs to.

Many PHP built-in functions accept callback or you can create your own function which accepts callback function. It iterates through every element of the array and applies the callback function to each element. The Original array remains untouched. So that is the subtle difference between an anonymous function and a closure. In fact, both are of them are instances of Closure class internally:.

Here we have made multiply function to require type of Closure as second parameter. If you look at it's definition , here is how it looks:. It means it expects something to be callable function. Anytime you see such parameter in some function definition, it means you can apply anonymous functions to it.

Here is example:. Anonymous functions are implemented using the Closure class. Closures can also be used as the values of variables; PHP automatically converts such expressions into instances of the Closure internal class. Assigning a closure to a variable uses the same syntax as any other assignment, including the trailing semicolon:. Closures may also inherit variables from the parent scope. Any such variables must be passed to the use language construct.

As of PHP 7. A return type declaration of the function has to be placed after the use clause. As of PHP 8. Inheriting variables from the parent scope is not the same as using global variables.

Global variables exist in the global scope, which is the same no matter what function is executing. The parent scope of a closure is the function in which the closure was declared not necessarily the function it was called from. See the following example:.