crt1.o：在函数_start中：（.text + 0x20）：对main的未定义引用

Question

I have a small piece of code, which gives this error when trying to make , here is the CMakelists.txt being used:

cmake_minimum_required(VERSION 2.8)                     #Specify the minimum CM$
project(gaussian)                                                              $
find_package(CUDA REQUIRED)                                     #find the CUDA $
find_package(ITK REQUIRED)

include( ${ITK_USE_FILE} )
#message("Debug: ITK ${ITK_DIR}")

include_directories(${CUDA_INCLUDE_DIRS})   #Specify the CUDA include direc$


add_executable(gaussian source/main.cu)                    #create an executabl$

#specify any additional libraries here (CUFFT and CUBLAS can be useful)
target_link_libraries(gaussian ${CUDA_cufft_LIBRARY} ${CUDA_cublas_LIBRARY} ${I$

The main.cu file is below:

#include <fstream>
#include <cuda.h>
#include <iostream>
#include <stdio.h>
#include <string>
#include <sstream>
#include <stdlib.h>
#include <math.h>
#include <time.h>
#include <ctime>
#include <cuda_runtime_api.h>
#include <cufft.h>
#include "itkImage.h"

using namespace std;
static void HandleError( cudaError_t err, const char *file, int line ) 
{
        if (err != cudaSuccess) 
                cout<<cudaGetErrorString(err)<<" in "<< file <<" at line "<< line<<endl;
}
#define HANDLE_ERROR( err ) (HandleError( err, __FILE__, __LINE__ ))
int main(int argc, char* argv[])
{
        typedef itk::Image< unsigned short, 3 > ImageType;
        ImageType::Pointer image = ImageType::New();
        cout << "ITK Hello World !" << endl;
        int nDevices;
        cout<<"DEVICE SPECIFICATIONS: "<<endl<<endl;
        HANDLE_ERROR(cudaGetDeviceCount(&nDevices)); 
        return 0;
}

While building, the linkers are set. I am unable to figure out what is wrong here.

Answer 1

I found the issue here, firstly as pointed I needed to use cuda_add_executable, instead of add_executable. Doing that and building, I get errors like:

overriding itk::ImageBase<VImageDimension>::Pointer
itk::ImageBase<VImageDimension>::CreateAnother() const [with unsigned int VImageDimension = 3u, itk::ImageBase<VImageDimension>::Pointer = itk::SmartPointer<itk::ImageBase<3u> >]

These are because the CUDA compiler has trouble with the C++ features used by ITK. Using the ITK features in a .cxx file and calling CUDA functions in .cu file helped.

Credits: http://public.kitware.com/pipermail/insight-developers/2012-October/022116.html