Documentation.

Author: ncruces

src/runtime/testdata/testwinsignal/main.go

@@ -11,26 +11,26 @@ import (
 )
 
 func main() {
-	// ensure that this process terminates when the test times out,
-	// even if the expected signal never arrives
+	// Ensure that this process terminates when the test times out,
+	// even if the expected signal never arrives.
 	go func() {
 		io.Copy(io.Discard, os.Stdin)
 		log.Fatal("stdin is closed; terminating")
 	}()
 
-	// register to receive all signals
+	// Register to receive all signals.
 	c := make(chan os.Signal, 1)
 	signal.Notify(c)
 
-	// get console window handle
+	// Get console window handle.
 	kernel32 := syscall.NewLazyDLL("kernel32.dll")
 	getConsoleWindow := kernel32.NewProc("GetConsoleWindow")
 	hwnd, _, err := getConsoleWindow.Call()
 	if hwnd == 0 {
 		log.Fatal("no associated console: ", err)
 	}
 
-	// close console window
+	// Send message to close the console window.
 	const _WM_CLOSE = 0x0010
 	user32 := syscall.NewLazyDLL("user32.dll")
 	postMessage := user32.NewProc("PostMessageW")
@@ -40,8 +40,14 @@ func main() {
 	}
 
 	sig := <-c
-	// pretend to take some time handling the signal
+
+	// Allow some time for the handler to complete if it's going to.
+	//
+	// (In https://go.dev/issue/41884 the handler returned immediately,
+	// which caused Windows to terminate the program before the goroutine
+	// that received the SIGTERM had a chance to actually clean up.)
 	time.Sleep(time.Second)
-	// print signal name, "terminated" makes the test succeed
+
+	// Print the signal's name: "terminated" makes the test succeed.
 	fmt.Println(sig)
 }