Question

I got some problems with the error “Link error LNK2005 … already defined”. The files are as follows:

// File Bitmap4.cu
#include "Bitmap4.h" // header
#include "Bitmaps_cuda.h" // header with just the definitions of the kernels

..... // I call 3+2 kernel functions (3 in one method, 1 in another and 1 in another one)

Then I have this one:

// File Bitmap8.cu
#include "Bitmap8.h" // header
#include "Bitmaps_cuda.h" // the same as above

..... // I call 4 kernel functions (4 in the same method)

Then I have the kernel header:

#ifndef __BITMAPS_KERNEL__
#define __BITMAPS_KERNEL__

......  // 9 kernels definitions

#endif

And finally, I have this one:

// File Bitmaps_cuda.h
#include <cuda.h>
#include <cuda_runtime.h>
#include <device_launch_parameters.h>
#include <device_functions.h>
#include <stdio.h>

// Inside here there all the kernel functions that the files 
// Bitmap4.cu and Bitmap8.cu are using

The problem is that, if i don’t include the #include “Bitmaps_cuda.h” in one of the Bitmap*.cu, of course, the compiler will say that I missed the definitions of the kernels functions. I read a lot of posts and i already included the “Additional Dipendencies” and the required PATHs. The problems started when I added the file Bitmap8.cu with its relative kernels, because before that, the application was working properly.

Anyway, those are the error that i have:

1>Bitmap8.cu.obj : error LNK2005: "void * __cdecl big_random_block(int(?big_random_block@@YAPAXH@Z) already defined in Bitmap4.cu.obj
1>Bitmap8.cu.obj : error LNK2005: "int * __cdecl big_random_block_int(int(?big_random_block_int@@YAPAHH@Z) already defined in Bitmap4.cu.obj
1>Bitmap8.cu.obj : error LNK2005: "unsigned char __cdecl value(float,float,int(?value@@YAEMMH@Z) already defined in Bitmap4.cu.obj
1>Bitmap8.cu.obj : error LNK2005: "void * __cdecl start_thread(unsigned int(__stdcall*)(void *),void *)" (?start_thread@@YAPAXP6GIPAX@Z0@Z) already defined in Bitmap4.cu.obj
1>Bitmap8.cu.obj : error LNK2005: "void __cdecl end_thread(void *)"(?end_thread@@YAXPAX@Z) already defined in Bitmap4.cu.obj
1>Bitmap8.cu.obj : error LNK2005: "void __cdecl destroy_thread(void *)"(?destroy_thread@@YAXPAX@Z) already defined in Bitmap4.cu.obj
1>Bitmap8.cu.obj : error LNK2005: "void __cdecl wait_for_threads(void * const *,int)"(?wait_for_threads@@YAXPBQAXH@Z) already defined in Bitmap4.cu.obj
1>Bitmap8.cu.obj : error LNK2005: "void __cdecl__device_stub__Z14float_to_colorPhPKf(unsigned char *,float const *)"(?__device_stub__Z14float_to_colorPhPKf@@YAXPAEPBM@Z) already defined in Bitmap4.cu.obj
1>Bitmap8.cu.obj : error LNK2005: "void __cdecl float_to_color(unsigned char *,float_const *)" (?float_to_color@@YAXPAEPBM@Z) already defined in Bitmap4.cu.obj
1>Bitmap8.cu.obj : error LNK2005: "void __cdecl__device_stub__Z14float_to_colorP6uchar4PKf(struct uchar4 *,float const *)"(?__device_stub__Z14float_to_colorP6uchar4PKf@@YAXPAUuchar4@@PBM@Z) already defined in Bitmap4.cu.obj
1>Bitmap8.cu.obj : error LNK2005: "void __cdecl float_to_color(struct uchar4 *,float_const *)" (?float_to_color@@YAXPAUuchar4@@PBM@Z) already defined in Bitmap4.cu.obj

1>C:\Users\dberdin\documents\visual studio 2010\Projects\gpuSPAM\Debug\gpuSPAM.exe : fatal error LNK1169: one or more multiply defined symbols found

I tried different solutions but with any results.

Thank you in advance!

EDIT

On the website (http://msdn.microsoft.com/en-us/library/72zdcz6f.aspx) i found that one of the causes of those errors is:
– An absolute is defined twice, with a different value in each definition.
Well, actually, as i wrote in the bottom, i have these kind of definetions, but i can’t do differently. Any idea how to solve it ?

Thank you again in advance

Answer 1

Those errors came because i double included a file. Problem Solved!