<p>Hey, I am a beginner and I just learned how to read user input with scan and its variable passed by reference.</p>
<p>for example,
var s1, s2, s3 string
n, _ := fmt.Scan(&s1, &s2, &s3)
fmt.Println(s1, s2, s3)</p>
<p>However, how would you get user input when you don't know when he stops typing?
I am trying to guide a user that he can stop by pressing ctrl+c, otherwise he could input as much as he want. </p>
<p>Then, i came up with making use of infinite for loop and pass a single variable by reference to fmt.Scan.
I do not know how to detect if he press ctrl+c.
What kind of functions available for this in Go?</p>
<hr/>**评论：**<br/><br/>echophant: <pre><p>Working example:</p>
<pre><code> package main
import (
"fmt"
"os"
"os/signal"
"syscall"
)
func main() {
// Go signal notification works by sending `os.Signal`
// values on a channel. We'll create a channel to
// receive these notifications (we'll also make one to
// notify us when the program can exit).
sigs := make(chan os.Signal, 1)
// `signal.Notify` registers the given channel to
// receive notifications of the specified signals.
signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
msg := make(chan string, 1)
go func() {
// Receive input in a loop
for {
var s string
fmt.Scan(&s)
// Send what we read over the channel
msg <- s
}
}()
loop:
for {
select {
case <-sigs:
fmt.Println("Got shutdown, exiting")
// Break out of the outer for statement and end the program
break loop
case s := <-msg:
fmt.Println("Echoing: ", s)
}
}
}
</code></pre>
<p>The signal code is taken from <a href="https://gobyexample.com/signals" rel="nofollow">Go by Example</a>. The key here is the select statement, which will wait until we receive input from either the user or the exit signal.</p></pre>tmornini: <pre><p>ctrl+c should NOT be used to end input, it should end the program.</p>
<p>ctrl+d is EOF and pretty much universally signals end-of-input.</p></pre>JuggleTux: <pre><p>also EOF makes it possible to pipe input to the program</p></pre>FUZxxl: <pre><p>Traditionally, you would end user input by having the user type a dot on a line on its own. That's how <code>ed</code>, <code>sendmail</code> and various other tools work. Another thing you could do is letting the user end input by typing Ctrl+D (or Ctrl+Z on Windows). This causes the terminal driver to signalize that input has ended. Your program notices by receiving an <code>io.EOF</code> error. Reacting to Ctrl+C is a bit more complicated. There are two ways:</p>
<ul>
<li>Catch SIGINT by registering a signal handler using <a href="https://golang.org/pkg/os/signal/" rel="nofollow"><code>os.signal</code></a> and somehow notify the reading Go routine that input ended (e.g. using a channel)</li>
<li>Reconfigure the terminal to accept Ctrl+C as the EOF marker for the duration of input using the <a href="http://golang.org/pkg/syscall/" rel="nofollow"><code>syscall</code></a> package and a lot of manual fiddling. Probably not worth the effort.</li>
</ul></pre>
