topic clSetKernelArg arg_value as NULL object. in OpenCL* for CPU

clSetKernelArg arg_value as NULL object.

dpshamonin — Fri, 04 Nov 2011 14:59:24 GMT

Hi,

According OpenCL 1.1 specification clSetKernelArg arg_value could be NULL object.
http://www.khronos.org/registry/cl/sdk/1.1/docs/man/xhtml/clSetKernelArg.html

So, the construction (below) is valid: 

cl_mem null_buffer = NULL;
errid = clSetKernelArg(m_KernelContainer[kernelIdx], argIdx, sizeof(cl_mem), &null_buffer);
OclCheckError(errid);

However, on Intel OpenCL SDK 1.5, I am keep getting error:
OpenCL Error : CL_INVALID_MEM_OBJECT

I've tried same construction on Nvidia OpenCL 1.1, it works fine. no error at all.
Am I missing something or that could be a bug?

Thanks,
-Denis

clSetKernelArg arg_value as NULL object.

Evgeny_F_Intel — Fri, 04 Nov 2011 15:50:45 GMT

Hi Denis,

According to the spec. you can pass the NULL pointer toas anargument if target parameter is a buffer.

From the spec:
"If the argument is a buffer object, the arg_value pointer can be

NULL or point to a NULL value in which case a NULL value will be used as the value for the

argument declared as a pointer to __global or __constant memory in the kernel"

We will try to reproduce the issue and update your accordingly.

Thanks,
Evgeny

clSetKernelArg arg_value as NULL object.

dpshamonin — Mon, 07 May 2012 11:58:58 GMT

Hi Again,

I've just recently checked this issue again with latest Intel 2012 x64 SDK.
It is still there!!!

We need this feature sometimes, otherwise we have to make different kernels with different number of arguments to work around it.

Could you please make a bug report and hopefully fix it for next release?
Thanks,

-Denis

clSetKernelArg arg_value as NULL object.

Shiri_M_Intel — Mon, 07 May 2012 12:19:03 GMT

Hi Denis

Thank you for your report.
This is a real bug.
We opened a ticket. It will be fixed in future releases...
Thanks, Shiri

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