Iphone: getting error "_AudioSessionSetProperty" when playing a recording

Question

I get an error,

Undefined symbols for architecture i386: "_AudioSessionSetProperty", referenced from 

while playing my recording. I turned on

 #import <AVFoundation/AVFoundation.h> #import <CoreAudio/CoreAudioTypes.h> #import <AudioToolbox/AudioToolbox.h> 

and its header files. what is missing?

Answer 1

Has AudioToolbox included in the app?