ifdef for device inside combined host device code what ifdef can i use to include only device specif

Accelerated Computing CUDA CUDA Programming and Performance
#1

I have some source files that are combined host device which works fine but sometimes I need a ifdef for host specific declarations like shared or some reduction step or something.
Something like
#if defined DeviceCode would be good. thanks.

#2

Use

#ifdef __CUDA_ARCH__

for that, as CUDA_ARCH is only defined when compiling for the device.