Beginner error in CUDA
- by Dimitri
Hi folks,
first all i want to wish you a merry christmas.
I am writing a small program in CUDA and i have the following errors :
contraste.cu(167): error: calling a host function from a __device__/__global__ function is not allowed
I don't understand why. Can you please help me and show me my errors. It seems that my program is correct. Here is a the bunch of code causing the problems :
__global__ void kernel_contraste(float power,
unsigned char tab_in[],
unsigned char tab_out[],
int nbl, int nbc) {
int x = threadIdx.x;
printf("I am the thread %d\n", x);
}
Part of my main program :
unsigned char *dimg, *dimg_res;
.....
cudaMalloc((void **)dimg, h * w * sizeof(char));
cudaMemcpy(dimg, r.data, h*w*sizeof(char), cudaMemcpyHostToDevice);
cudaMalloc((void **)dimg_res, h*w*sizeof(char));
dim3 nbThreadparBloc(256);
dim3 numblocs(1);
kernel_contraste<<<numblocs, nbThreadparBloc >>>(puissance, dimg, dimg_res, h, w);
cudaThreadSynchronize();
.....
cudaFree(dimg);
cudaFree(dimg_res);
The line 167 is the line where i call the printf in function kernel_contraste.
For information, this program takes an image as an input( a sun Rasterfile ) and a power then it calculates the contraste of that image.
Thanks !!
