What are ref functions in D?

What is a function?

Functions are generally code blocks that carry out certain instructions in an application. This code block can be called more than once during the application's run time or execution time if its functions are reusable.

What are ref functions?

ref functions are functions that return by reference. This is similar to the arguments of the ref function. For a better understanding, let's look at an example:

import std.stdio;
ref int lesser(ref int val1, ref int val2) { 
   return val1; 
} 
 
void main() {
   int x = 1; 
   int y = 2;  
   
   lesser(x, y) += 10;   
   writefln("x: %s, y: %s", x, y);   
}

Code explanation

In the example above, we add 10 to val1 returned from the function.

  • Line 3: Notice the use of the ref keyword and its use in the arguments also.
  • Line 4: We return val1 to demonstrate the ref function.
  • Line 8-9: We declare our variables.
  • Line 11: We call the ref function. Here, we use it as a variable. We add 10 to val1 since we only return val1 from the ref function.
  • Line 12: We printed our output to the screen.

Free Resources

License: Creative Commons-Attribution-ShareAlike 4.0 (CC-BY-SA 4.0)