C++/CUDA: unresolved external symbol "enum cudaError ..." - c++

Question

There are quite a lot similar posts concerning this topic here on SO, however so far I couldn't find a solution to my issue.
I want to add CUDA functionality to an existing C++ project (Window, Visual Studio 2019). Here is what I did so far (based on what I gathered googling around).
Solution Explorer -> Right-Click on Project -> Build Dependencies -> Build Customization -> Tick Checkbox for CUDA 11.2 (.targets, .props)
Created a new 'dummy' CUDA project from Visual Studio, build and started it (VS2019 creates a small project, which adds items of two arrays using CUDA on the GPU). It worked.
Checked and compared Project properties between my existing project and the 'dummy' project and changed the following options:
CUDA C/C++ -> Target Machine Platform -> 64-Bit
Linker -> Additional Dependencies -> added cudart_static.lib
Next I created a class with some test code (which is pretty much completely taken from the 'dummy' project):
SHCalculator.h:
#pragma once
class SHCalculator
{
private:
public:
void DoTestCalculationWithCuda();
};
SHCalculator.cpp:
#include "pch.h"
#include "SHCalculator.h"
#include "SHCalculation.cuh"
void SHCalculator::DoTestCalculationWithCuda()
{
const int arraySize = 5;
const int a[arraySize] = { 1, 2, 3, 4, 5 };
const int b[arraySize] = { 10, 20, 30, 40, 50 };
int c[arraySize] = { 0 };
cudaError_t cudaStatus = AddWithCuda(c, a, b, arraySize);
if (cudaStatus != cudaSuccess) {
fprintf(stderr, "addWithCuda failed!");
return;
}
printf("{1,2,3,4,5} + {10,20,30,40,50} = {%d,%d,%d,%d,%d}\n",
c[0], c[1], c[2], c[3], c[4]);
// cudaDeviceReset must be called before exiting in order for profiling and
// tracing tools such as Nsight and Visual Profiler to show complete traces.
cudaStatus = cudaDeviceReset();
if (cudaStatus != cudaSuccess) {
fprintf(stderr, "cudaDeviceReset failed!");
return;
}
}
SHCalculation.cuh:
cudaError_t AddWithCuda(int* c, const int* a, const int* b, unsigned int size);
//__global__ void addKernel(int* c, const int* a, const int* b);
SHCalculation.cu:
#include "pch.h"
#include "SHCalculation.cuh"
//__global__ void addKernel(int* c, const int* a, const int* b)
//{
// int i = threadIdx.x;
// c[i] = a[i] + b[i];
//}
cudaError_t AddWithCuda(int* c, const int* a, const int* b, unsigned int size)
{
int* dev_a = 0;
int* dev_b = 0;
int* dev_c = 0;
cudaError_t cudaStatus = cudaError_t::cudaErrorAssert;
// left out all the other code (memory allocation, kernel calling) here, since the error
// comes without it as well.
return cudaStatus;
}
Notice, I have commented out or removed a lot of the code, as the error appears regardless. This are the error messages:
LNK2019 unresolved external symbol "enum cudaError __cdecl AddWithCuda(int *,int const *,int const *,unsigned int)" (?AddWithCuda##YA?AW4cudaError##PEAHPEBH1I#Z) referenced in function "public: void __cdecl SHCalculator::DoTestCalculationWithCuda(void)" (?DoTestCalculationWithCuda#SHCalculator##QEAAXXZ)
LNK1120 1 unresolved externals
Additional Info:
CUDA includes are in the precompiled header pch.h:
// cuda
#include "cuda_runtime.h"
#include "device_launch_parameters.h"
What could be the reason for the linker error?

Answer 1

Here is what was missing:
For all CUDA files do:
Right-Click -> Properties
In Configuration Properties -> General -> Item Type choose CUDA C/C++
This is the reason that no *.obj files where created and the linker couldn't link them.