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[sajis997]

Hi forum,

I am allocating a host memory and then i am creating a device memory buffer with the host copy pointer.

Do i have to explicitly copy the contents from host to device then?

If the host pointer is null while creating the device read & write buffer , then i think you need to copy explicitly from host to device later in the program .

What do you guys think?

Regards

Sajjad

[jberry · Accepted solution]

You don't need to copy the contents when you create the buffer - you can copy data from host memory in to the buffer later with clEnqueueWriteBuffer. e.g. for some integers in A:

....
int *A = malloc(n*sizeof(int));
cl_uint error;
cl_mem buffer = clCreateBuffer(context, CL_MEM_READ_WRITE, n*sizeof(*A), NULL, &error);
....
error = clEnqueueWriteBuffer(queue, buffer, CL_TRUE, 0, n*sizeof(*A), A, 0 NULL,NULL);

The specification is here: http://www.khronos.org/registry/cl/sdk/1.0/docs/man/xhtml/clEnqueueWriteBuffer.html