The **`Fprintln` function** in the Go programming language is used to print out a formatted string to the destination of your choosing. `Fprintln` does not support custom format specifiers, which means only the default formats are used to format the `string`. `Fprintln` also appends a newline character at the end of the string.


To use this function, you must import the `fmt` package in your file and access the `Fprintln` function within using the `.` notation: `fmt.Fprintln`. Here, `Fprintln` is the actual function, while `fmt` is the Go package that stores the definition of this function.

# Function definition

The definition of the `Fprintln` function inside the `fmt` package is as follows:


# Parameters

* **`dest`**: The destination where the formatted string is to be printed. This should be an object of type `io.Writer`. 

>**`io.Writer`** objects are, in simple terms, objects that have a built-in `write` method.

* **`a ...interface{}`**: The list of all arguments that need to be formatted and printed.

# Return values

The `fmt.Fprintln` function can return two things:

* **`count`**: The number of bytes that were written to the standard output.


* **`err`**: Any error thrown during the execution of the function.

# Examples
In the following example, we use the `Fprintln` function to print out a single string formatted string (including an integer value), first to a buffer variable of type `bytes.Buffer`. Then, we use the normal `Print` function to write the buffer to the standard output. 

> The `bytes` data type has a built-in `write` function, making it a compatible argument to send to the `Fprintln` function. To use the `Buffer` data type, you need to import the `bytes` package.

package main

import (
	"fmt"
  "bytes"
)

func main() {
  // declaring variables of different datatypes
  var message string = "Hello and welcome to"
  var year int = 2021

  // temporary buffer
  var temp_buff bytes.Buffer

	// printing out the declared variables as a single string
	fmt.Fprintln(&temp_buff, message, year)

  fmt.Print(&temp_buff)

}

In this second example, we print out a single string along with an integer value, directly to the standard output. Here, we also use the return values to print out relevant data for the `Fprintln` function used:

> The standard input/output is defined in the `os` package, so you need to include that in your file first.

package main

import (
	"fmt"
	"os"
)

func main() {

    // declaring variables of different datatypes
	var message string = "Hello and welcome to Educative \n"
	
	// storing the return values of Fprintln
	char_count, error := fmt.Fprintln(os.Stdout, message)

	if error == nil  {
		fmt.Print("Fprint executed without errors and wrote ",char_count, " characters")
	}

}

What is the Golang function Fprintln?

The Fprintln function in Go prints a formatted string to a specified destination using default formats, appending a newline character.