What are the differences in outcome for panic vs log.Fatalln()?
<p>From the documentation on <a href="https://golang.org/pkg/log/#Fatalln" rel="noreferrer">log.Fatalln()</a>:</p>

<blockquote>
  <p>func Fatalln(v ...interface{}) Fatalln is equivalent to Println()
  followed by a call to os.Exit(1).</p>
</blockquote>

<p>The <a href="https://golang.org/src/log/log.go" rel="noreferrer">source code</a> for Fatalln:</p>

<pre><code>   310  // Fatalln is equivalent to Println() followed by a call to os.Exit(1).
   311  func Fatalln(v ...interface{}) {
   312      std.Output(2, fmt.Sprintln(v...))
   313      os.Exit(1)
   314  }
</code></pre>

<p>It seems the main difference is whether or not the error is recoverable (since you can recover a panic) - is there anything more significantly different between these? </p>

<p>Panic's interface <a href="https://golang.org/src/builtin/builtin.go?h=func+panic" rel="noreferrer">definition</a> is:</p>

<pre><code>   215  // The panic built-in function stops normal execution of the current
   216  // goroutine. When a function F calls panic, normal execution of F stops
   217  // immediately. Any functions whose execution was deferred by F are run in
   218  // the usual way, and then F returns to its caller. To the caller G, the
   219  // invocation of F then behaves like a call to panic, terminating G's
   220  // execution and running any deferred functions. This continues until all
   221  // functions in the executing goroutine have stopped, in reverse order. At
   222  // that point, the program is terminated and the error condition is reported,
   223  // including the value of the argument to panic. This termination sequence
   224  // is called panicking and can be controlled by the built-in function
   225  // recover.
   226  func panic(v interface{})
</code></pre>

<p>It appears panic does not return anything.</p>

<p>Is that the primary difference? Otherwise, they seem to perform the same function in an application, assuming the panic is not recovered.</p>