Jack/earpiece detection in iphone

Anyone could tell me how to detect when a jack of an earpiece is plugged-i开发者_JS百科n into an ipad or iphone?

Thanks

I believe you can call AudioSessionGetProperty and then get the value "kAudioSessionProperty_AudioInputAvailable" to detect whether an audio jack has been plugged in.

I.e.

AudioSessionInitilize(NULL, NULL, NULL, NULL);
UInt32 propertySize, micConnected;
AudioSessionGetProperty(kAudioSessionProperty_AudioInputAvailable, &propertySize, &micConnected);