package main import ( "log" "github.com/BurntSushi/xgb" ) func init() { log.SetFlags(0) } func get32(buf []byte) uint32 { v := uint32(buf[0]) v |= uint32(buf[1]) << 8 v |= uint32(buf[2]) << 16 v |= uint32(buf[3]) << 24 return v } func main() { X, err := xgb.NewConn() if err != nil { log.Fatal(err) } root := X.DefaultScreen().Root aname := "_NET_ACTIVE_WINDOW" atom, err := X.InternAtom(true, uint16(len(aname)), aname) if err != nil { log.Fatal(err) } reply, err := X.GetProperty(false, root, atom.Atom, xgb.GetPropertyTypeAny, 0, (1<<32)-1) log.Printf("%X", get32(reply.Value)) }