Sandbox project to help understand issue discussed at https://github.com/BrownBiomechanics/Autoscoper/pull/238

CMakeLitsts.txt

cmake_minimum_required(VERSION 3.17.5)

message(STATUS "ENV{CUDA_PATH} [$ENV{CUDA_PATH}]")
message(STATUS "---- CMAKE_CUDA_COMPILER [${CMAKE_CUDA_COMPILER}]")

project(Sandbox)

set(CMAKE_CUDA_STANDARD 14)
set(CMAKE_CUDA_STANDARD_REQUIRED TRUE)

option(ENABLE_CUDA_LANGUAGE_FIRST "Enable CUDA first" ON)

message(STATUS "ENABLE_CUDA_LANGUAGE_FIRST: ${ENABLE_CUDA_LANGUAGE_FIRST}")

if(ENABLE_CUDA_LANGUAGE_FIRST)
  enable_language(CUDA)
  message(STATUS "----")
  message(STATUS "---- (after enable_language) CMAKE_CUDA_COMPILER [${CMAKE_CUDA_COMPILER}]")
  message(STATUS "----")
  
  find_package(CUDAToolkit REQUIRED)
  message(STATUS "----")
  message(STATUS "---- (after find_package) CMAKE_CUDA_COMPILER [${CMAKE_CUDA_COMPILER}]")
  message(STATUS "----")

else()

  find_package(CUDAToolkit REQUIRED)
  message(STATUS "----")
  message(STATUS "---- (after find_package) CMAKE_CUDA_COMPILER [${CMAKE_CUDA_COMPILER}]")
  message(STATUS "----")

  #set(CMAKE_CUDA_COMPILER ${CUDAToolkit_NVCC_EXECUTABLE})

  #message(STATUS "----")
  #message(STATUS "---- (expicitly setting) CMAKE_CUDA_COMPILER [${CMAKE_CUDA_COMPILER}]")
  #message(STATUS "----")

  # See https://cmake.org/cmake/help/latest/envvar/CUDACXX.html#cudacxx
  set(ENV{CUDACXX} ${CUDAToolkit_NVCC_EXECUTABLE})

  message(STATUS "----")
  message(STATUS "---- (expicitly setting) ENV{CUDACXX} [$ENV{CUDACXX}]")
  message(STATUS "----")

  enable_language(CUDA)
  message(STATUS "----")
  message(STATUS "---- (after enable_language) CMAKE_CUDA_COMPILER [${CMAKE_CUDA_COMPILER}]")
  message(STATUS "----")
endif()