package main

import (
	"log"
	"net"
	"runtime"
)

func main() {
	_, err := net.LookupIP("localhost")
	if err != nil {
		log.Fatalf("dns-err=%q", err)
	}

	if count := runtime.NumCgoCall(); count > 0 {
		log.Fatalf("cgo-calls=%d", count)
	}
}
