gistfile1.m

// get sample rate of the default input device
OSStatus MyGetDefaultInputDeviceSampleRate(Float64 *outSampleRate)
{
	OSStatus error;
	AudioDeviceID deviceID = 0;
	
	// get the default input device
	AudioObjectPropertyAddress propertyAddress;
	UInt32 propertySize;
	propertyAddress.mSelector = kAudioHardwarePropertyDefaultInputDevice;
	propertyAddress.mScope = kAudioObjectPropertyScopeGlobal;
	propertyAddress.mElement = 0;
	propertySize = sizeof(AudioDeviceID);
	error = AudioHardwareServiceGetPropertyData(kAudioObjectSystemObject, &propertyAddress, 0, NULL, &propertySize, &deviceID);
	if (error) return error;
	
	// get its sample rate
	propertyAddress.mSelector = kAudioDevicePropertyNominalSampleRate;
	propertyAddress.mScope = kAudioObjectPropertyScopeGlobal;
	propertyAddress.mElement = 0;
	propertySize = sizeof(Float64);
	error = AudioHardwareServiceGetPropertyData(deviceID, &propertyAddress, 0, NULL, &propertySize, outSampleRate);
	
	return error;
}

Well doesn't this look like fun