Merge pull request #32 from scr-oath/copy-return-err

Author: scr-oath

ioutil/README.md

@@ -19,7 +19,8 @@ local input_fh, err = io.open("./test/file.test", "r")
 assert(not err, err)
 local output_fh, err = io.open("./test/file2.data", "w")
 assert(not err, err)
-ioutil.copy(output_fh, input_fh)
+err = ioutil.copy(output_fh, input_fh)
+assert(not err, err)
 input_fh:close()
 output_fh:close()
 ```

ioutil/api.go

@@ -40,7 +40,8 @@ func Copy(L *lua.LState) int {
 	reader := lio.CheckIOReader(L, 2)
 	L.Pop(L.GetTop())
 	if _, err := io.Copy(writer, reader); err != nil {
-		L.RaiseError(err.Error())
+		L.Push(lua.LString(err.Error()))
+		return 1
 	}
 	return 0
 }
@@ -51,7 +52,8 @@ func CopyN(L *lua.LState) int {
 	n := L.CheckInt64(3)
 	L.Pop(L.GetTop())
 	if _, err := io.CopyN(writer, reader, n); err != nil {
-		L.RaiseError(err.Error())
+		L.Push(lua.LString(err.Error()))
+		return 1
 	}
 	return 0
 }