github.com/ccccaoqing/test@v0.0.0-20220510085219-3985d23445c0/doc/progs/eff_unused2.go (about) 1 // compile 2 3 package main 4 5 import ( 6 "fmt" 7 "io" 8 "log" 9 "os" 10 ) 11 12 var _ = fmt.Printf // For debugging; delete when done. 13 var _ io.Reader // For debugging; delete when done. 14 15 func main() { 16 fd, err := os.Open("test.go") 17 if err != nil { 18 log.Fatal(err) 19 } 20 // TODO: use fd. 21 _ = fd 22 }