CODEWITHSUNDEEP
opencl
All The Rage
All The Rage

Reputation: 831

How can I query the size of an OpenCL kernel argument?

I want to query the size of an OpenCL kernel argument so that I can ensure that I send it a variable of the correct size. I am able to query lots of other properties of each kernel argument using clGetKernelArgInfo, as follows:

clGetKernelArgInfo(k, argc, CL_KERNEL_ARG_TYPE_NAME, sizeof(argType), &argType, &retSize);

This will tell me the string name of the type, for example. But that's not good enough, especially in complex cases where it's a struct and the string name is the same on host and device, but the packing is different, so the size is different. The things that I can query, according to https://man.opencl.org/clGetKernelArgInfo.html , are:

CL_KERNEL_ARG_ADDRESS_QUALIFIER
CL_KERNEL_ARG_ACCESS_QUALIFIER 
CL_KERNEL_ARG_TYPE_NAME        
CL_KERNEL_ARG_TYPE_QUALIFIER   
CL_KERNEL_ARG_NAME

Any ideas?

FYI, this is NOT a duplicate of Get OpenCL Kernel-argument information because that is asking how to use the argument query function, not asking how to query the argument size.

Upvotes: 1

Views: 390

Answers (1)

apetranzilla
apetranzilla

Reputation: 5919

There's no standard way to check before setting the argument as far as I'm aware, but the clSetKernelArg call will return CL_​INVALID_​ARG_​SIZE if the sizes don't match properly, so that should allow you to detect and handle errors accordingly:

CL_INVALID_ARG_SIZE if arg_size does not match the size of the data type for an argument that is not a memory object or if the argument is a memory object and arg_size != sizeof(cl_mem) or if arg_size is zero and the argument is declared with the __local qualifier or if the argument is a sampler and arg_size != sizeof(cl_sampler).

Upvotes: 2

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