not able to use printf in cuda kernel function

Question

It seems that printf doesn\'t work inside the Kernel of a cuda code

#include \"Common.h\"
#include
#include 

__dev         


        

Answer 1

You need to use cuPrintf, as in this example. Note that printf is a pretty limited way of debugging, the Nsight or Nsight eclipse edition IDEs are much nicer.

Answer 2

Quoting the CUDA Programming Guide "Formatted output is only supported by devices of compute capability 2.x and higher". See the programming guide for additional information.

Devices of compute capability < 2.x can use cuPrintf.

If you are on a 2.x and above device and you are trying to use printf make sure you have specified arch=sm_20 (or higher). The default is sm_10 which does not have sufficient features to support printf.

NVIDIA offers three source level debuggers for CUDA. You may find these more useful than printf for inspecting variables. - Nsight Visual Studio Edition CUDA Debugger - Nsight Eclipse Edition CUDA Debugger - cuda-gdb