This file uses the classic non-ARC retain/release model

Hi gays, i have a problem with non-arc. when i put code into my project. it show me an error with "This file uses the classic non-ARC retain/release model; hints below".
i put openudid.mm into build phases - compile source, and mark it with "-fno-objc-arc".
but it doesn't work.
i'm not a object-c programmer. so it make me confused.
by the way. the image url in code is missing.