clGetKernelArgInfo

Returns information about the arguments of a kernel.

cl_int clGetKernelArgInfo ( cl_kernel  kernel ,
  cl_uint  arg_indx ,
  cl_kernel_arg_info  param_name ,
  size_t  param_value_size ,
  void  *param_value ,
  size_t  *param_value_size_ret )

Parameters

kernel

Specifies the kernel object being queried.

arg_indx

The argument index. Arguments to the kernel are referred by indices that go from 0 for the leftmost argument to n - 1, where n is the total number of arguments declared by a kernel.

param_name

Specifies the argument information to query. The list of supported param_name types and the information returned in param_value by clGetKernelArgInfo is described in the table below.

param_value

A pointer to memory where the appropriate result being queried is returned. If param_value is NULL, it is ignored.

param_value_size

Used to specify the size in bytes of memory pointed to by param_value. This size must be > size of return type as described in the table below.

cl_kernel_arg_info Return Type Info. returned in param_value
CL_KERNEL_ARG_ADDRESS_QUALIFIER cl_kernel_arg_- address_qualifier

Returns the address qualifier specified for the argument given by arg_indx. This can be one of the following values:


CL_KERNEL_ARG_ADDRESS_GLOBAL
CL_KERNEL_ARG_ADDRESS_LOCAL
CL_KERNEL_ARG_ADDRESS_CONSTANT
CL_KERNEL_ARG_ADDRESS_PRIVATE
                                        

If no address qualifier is specified, the default address qualifier which is CL_KERNEL_ARG_ADDRESS_PRIVATE is returned.

CL_KERNEL_ARG_ACCESS_QUALIFIER cl_kernel_arg_- access_qualifier

Returns the access qualifier specified for the argument given by arg_indx. This can be one of the following values:


CL_KERNEL_ARG_ACCESS_READ_ONLY
CL_KERNEL_ARG_ACCESS_WRITE_ONLY
CL_KERNEL_ARG_ACCESS_READ_WRITE
CL_KERNEL_ARG_ACCESS_NONE
                                        

If argument is not an image type, CL_KERNEL_ARG_ACCESS_NONE is returned. If argument is an image type, the access qualifier specified or the default access qualifier is returned.

CL_KERNEL_ARG_TYPE_NAME char[]

Returns the type name specified for the argument given by arg_indx. The type name returned will be the argument type name as it was declared with any whitespace removed. If argument type name is an unsigned scalar type (i.e. unsigned char, unsigned short, unsigned int, unsigned long), uchar, ushort, uint and ulong will be returned. The argument type name returned does not include any type qualifiers.

CL_KERNEL_ARG_TYPE_QUALIFIER cl_kernel_arg- type_qualifier

Returns the type qualifier specified for the argument given by arg_indx. The returned value can be: CL_KERNEL_ARG_TYPE_CONST, CL_KERNEL_ARG_TYPE_RESTRICT, CL_KERNEL_ARG_TYPE_VOLATILE, a combination of the above enums or CL_KERNEL_ARG_TYPE_NONE.

NOTE: CL_KERNEL_ARG_TYPE_VOLATILE is returned if the argument is a pointer and the pointer is declared with the volatile qualifier.

CL_KERNEL_ARG_NAME char[]

Returns the name specified for the argument given by arg_indx.

param_value_size_ret

Returns the actual size in bytes of data copied to param_value. If param_value_size_ret is NULL, it is ignored.

Notes

Kernel argument information is only available if the program object associated with kernel is created with clCreateProgramWithSource and the program executable is built with the -cl-kernel-arg-info option specified in options argument to clBuildProgram or clCompileProgram.

Errors

Returns CL_SUCCESS if the function is executed successfully. Otherwise, it returns one of the following errors:

  • CL_INVALID_ARG_INDEX if arg_indx is not a valid argument index.
  • CL_INVALID_VALUE if param_name is not valid, or if size in bytes specified by param_value_size is < size of return type as described in the table above and param_value is not NULL
  • CL_KERNEL_ARG_INFO_NOT_AVAILABLE if the argument information is not available for kernel.
  • CL_INVALID_KERNEL if kernel is not a valid kernel object.

Specification

OpenCL Specification

Also see

clCreateKernel, clGetKernelInfo, clCreateKernelsInProgram, clRetainKernel, clReleaseKernel, clSetKernelArg, clGetKernelWorkGroupInfo

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